AbstractDineutus Macleay, 1825 are treated. The New World Dineutus are found to be composed of 18 species and 6 subspecies: one species, Dineutusmexicanus Ochs, 1925, stat. n. is elevated from subspecies to species rank, and the subspecies Dineutuscarolinusmutchleri Ochs, 1925, syn. n. is synonymized here with the typical form. Lectotypes are designated for Dineutusdiscolor Aubé, 1838, Dineutesmetallicus Aubé, 1838, Dineutussolitarius Aubé, 1838, Dineutesanalis Régimbart, 1883, and Gyrinuslongimanus Olivier, 1795. Each taxonomic unit is provided with a taxonomic history, type locality, diagnosis, distribution, habitat information, and a discussion section. The aedeagus and male mesotarsal claws are illustrated, and dorsal and ventral habitus images of both sexes, for each species and subspecies are provided. General distribution maps are provided for all taxonimc units. A key to the genera of New World Gyrinidae, as well as all the New World Dineutus species is provided. General Dineutus anatomy as well as a clarification of homology and anatomical terms is included.All New World members of the whirligig beetle genus  Dineutus Macleay, 1825 is represented in the New World by 18 species and 6 subspecies. Members of Dineutus are among the largest of all New World whirligig beetles found in North and Central America, where they are common elements of aquatic environments including ponds, lakes, rivers, and streams. The genus is known from tropical regions around the world, but is notably absent from South America  which he placed in the subgenus Rhombodineutus Ochs, 1926b  and Dineutustruncatus  which he maintained in Dineutuss. str.Cyclinus without any diagnosis aside from their distribution in North America. To confound matters even more, Dineutus species are indeed monophyletic. The phylogenetics of the genus Dineutus, as well as the rest of the dineutine genera and subgenera, will be addressed in a future paper, potentially providing better evidence regarding the monophyly and potential synapomorphies for the North American Dineutus. Until that can be done, we recommend discontinued use of the subgenus name Dineutus (Cyclinus) for the New World species until its monophyly and diagnostic combination can be investigated more thoroughly.Classically, the genus Dineutus. It is our hope that this work will help improve identification of material within public and private collections and help facilitate research on stream ecology, and aspects of these charismatic beetles’ behavior and biology. This work greatly improves upon previous identification materials by introducing a novel external character for use in identification , providing high-quality habitus photos for each taxon, detailed aedeagal illustrations, distributions maps, and in-depth differential diagnoses.This work is meant to allow for the accurate identification of all the New World species and subspecies of PageBreakDineutus species has focused on aspects of their behavior, especially those associated with their water-surface aggregrations. Many of the common Dineutus of North America are known to form giant multispecies and sometimes multigeneric . It is well established that these mass aggregations operate as a selfish herd , Dineutushornii Roberts, 1895, Dineutusnigrior Roberts, 1895, and Dineutusdiscolor Aubé, 1838, making it clear Dineutus species present excellent candidates for model study systems for a variety of areas of study.The vast majority of published research on, or utilising, New World igeneric  aggregraish herd  for predish herd . Severalish herd , others ish herd . Studiesish herd  and evidish herd ; 1967 haish herd  and avoiish herd  has beenish herd . Aspectsish herd . Studiesish herd ; 2013. NDineutus are, studies on their life history, and juvenile stages are shockingly missing. The general lack of life history knowledge for all North America water beetles was pointed out as early as the 1920’s by Dineutusassimilis in his note on behavior, but this was mostly anecdotal. Dineutusassimilis, Dineutushornii, and Dineutusnigrior, including adult and larval durations for Dineutusnigrior and Dineutushornii, later (1967) adding anecdotal pupal information for the later two species, but this was not the focus of Istock’s studies. The juvenile stages have similarly never been formally studied and described for any species, with the exception of Dineutusassimilis. Dineutusassimilis, including illustrations, and given the date of this work it is quite exceptional. Despite Dineutusassimilis, Dineutushornii, and Dineutusnigrior are provided in Spanglerogyrus Folkerts, 1979, for which larvae remain unknown , as it was not necessary in order to have all species accounted for in this study. The second author has visited the Smithsonian Institution sensuFor each species a taxonomic history is provided. This list is a partial chresonomy Measurements were taking using a Cen-Tech 4 inch Digital Caliper (ITEM 47256).Total body lengths were measured from the anterolateral margin of the clypeus to the apex of the elytral apices. These areas were chosen for the boundaries of lengths since they are more fixed than other possible boundaries. For example, the labrum may be depressed thereby making it a poor choice as an anterior boundary, and the abdomen may be more or less protruding making it an unsuitable posterior boundary. For each species and subspecies an attempt was made to measure the largest and smallest specimens available for each sex.Specimens for dissections and imaging were relaxed by placing them in lightly boiling water.The aedeagus was then dissected from relaxed males and placed in warm 10% KOH for about 5 minutes. Following removal from KOH the aedeagus was placed in vinegar to neutralize the base and washed in water. After dissection and/or imaging aedeagi were placed in microvials attached to the pin with the original specimens.Images of non-aedeagal structures were drawn using a camera lucida attached to a Zeiss Discovery V8 stereo microscope. For aedeagi, drawings were made using Adobe Illustrator by tracing and modifying light photography images subsequently modified in Adobe Photoshop.www.visionarydigital.com, R. Larimer).Dorsal, ventral habitus as well as aedeagal images were taken using a Visionary Digital BK+ light imaging system EMEC Florida State Collection of Arthropods, Gainesville, Florida, U.S.A. (M. Thomas)FSCA Grey T. Gustafson personal collection.GTGC Instituto de Ecologia, A.C. Xalapa, Veracruz, Mexico (R. Arce-Pérez)IEXA Division of Entomology, University of Kansas Natural History Museum, Lawrence, Kansas, U.S.A. (A.E.Z. Short)KSEMPageBreakhttp://insects.oeb.harvard.edu/mcz/ Museum of Comparative Zoology, Harvard University, Cambridge, Massachusettes, U.S.A. Material from this collection was not loaned, it was examined online via MCZ Musée National d’Histoire Naturelle, Paris, France (A. Mantilleri)MNHN Museum of Southwestern Biology Arthropod Division, University of New Mexico, Albuquerque, New Mexico, U.S.A. (K.B. Miller)MSBA Montana Entomology Collection, Montana State University, Bozeman, Montana, U.S.A. (M. Ivie)MTEC National Museum, Prague, Czech Republic (M. Fikáček)NMPC University of California Entomology Research Museum, Department of Entomology, Riverside, California, U.S.A. (D. Yanega)UCRC West Indian Beetle Fauna Project, Montana Entomology Collection, Bozeman, Montana, U.S.A. (M. Ivie)WIBF Museum für Naturkunde der Humboldt Universitat zu Berlin, Berlin, Germany (M. Uhlig)ZMHBGyrinidae the current position of all the legs are different from the ancestral condition within Adephaga. Gyrinidae have their prothoracic legs rotated ca. 90° anteriorly in normal anatomical repose, whereas the meso- and metathoracic legs have been rotated ca. 90° posteriorly, similar to the condition in Dytiscidae .PageBreakDineutus within the New World. A key to the genera of Gyrinidae within the New World as well as to all the species of Dineutus is provided. The key to species works for both males and females. The identification of Dineutus can be done without many difficulties using only external characters. However, several characteristics of the genus make identification somewhat difficult. First, males and females tend to be dimorphic with the females of several species appearing very similar . Whereas gyrinids are often collected in large rafts or aggregrates, these aggregates often contain multiple species or even multiple genera : The mesotarsal claws of New World Dineutus are sexually dimorphic, a feature that has been overlooked in previous treatments of the group. Males have the mesotarsal claws modified in several ways causing them to differ significantly from the metatarsal claws, whereas the mesotarsal claws of females are more similar in form to the metatarsal claws in terms of size and shape. The mesotarsal claws of females do differ from the metatarsal claws, however, not to the degree of the male’s. The modifications to the male mesotarsal claws include increased size : The overall shape of the male protibia has been historically used as a diagnostic character : The profemora of New World PageBreakDineutus possess a very distinct, large denticle located sub-apically on the posterior margin of the ventral surface , but for the purpose of this study only the sub-apicoventral denticle, referred to through the rest of this paper as the profemoral sub-apicoventral tooth, was used for diagnostic purposes, as the development of the more basal denticles varied noticeably within species. One species, Dineutusproductus, has a unique dentation consisting of a series of denticles along the femoral margin with each denticle associated with a setigerous puncture, and the sub-apicoventral tooth distinct.There are other variants of the dentation of the ventral profemora of North American Elytral apices : The elytral apices are highly diagnostic for North American Dineutus , as in Dineutusmexicanus or Dineutusproductus, with the character varying both within and among populations. Some species never have serrations and/or irregularities present.tus Fig. . The elytus Fig. . This seDineutuscarolinus : The shape of the antennae is useful for identification with overall thickness and appearance of the ultimate antennomere useful for distinguishing very similar species like Dineutushornii and Dineutusassimilis, especially when comparing female specimens. But in general antennal shape alone is not diagnostic.ape Fig.  ante: ThAedeagus : For this study the male aedeagus was considered to be an important indicator of species boundaries. The male aedeagus is by far the best diagnostic feature for species identification of North American Dineutus. Most species have clear and easily distinguishable characters associated with the aedeagus, including the shape of the median lobe, the shape of the sperm-groove, and the shape of parameres. The aedeagus is best viewed in the dorsal aspect : In the past, the number of setigerous profemoral punctures present on the anterior surface of the prothoracic legs has been used as a diagnostic character for separating species  and is not a result of preservation. For this reason, dorsal coloration is described but is not used as a comprehensively diagnostic feature.PageBreakTaxon classificationAnimaliaColeopteraGyrinidaeHatch, 1930Dineutus (Cyclinus) amazonicus Hatch, 1930: 16.U.S.A., Arkansas, “Sevier Co., Ark. Saline R. about 18 miles east of DeQueen.”None–see comments below in Discussion.PageBreakMale: unknown.Female: Length 10 mm, elytral apices regularly oval, serration absent, lateral margins weakly sinuate, profemora of female with apicoventral tooth present running 1/5 its length.Known only from the type locality.UnknownDineutusamazonicus was described from a single female specimen collected in Arkansas during the 1930’s. The species, as described by Hatch (1930), is unique among all other North American Dineutus in having females with an sub-apicoventral tooth present on the profemora, running approximately 1/5 its length. In Dineutus this is a commonly sexually dimorphic character, with the tooth present only in males. Hatch (1930) indicated the elytra of this species are similar to those of Dineutusemarginatus, being regularly rounded and lacking serration.Dineutusamazonicus . It appears that the type may be missing, and that no other published records of this species have occurred since its description in 1930. Although Hatch’s (1930) description at first sounds dubious, as the profemoral sub-apicoventral tooth is in all other species unique to males, Hatch was unlikely to mistake a female gyrinid for a male  or Oregon State University  where Hatch’s collection was deposited. No specimens in the University of Arkansas collection were identified as r a male , 1926, aDineutusciliatus as described by Hatch (1930), but unsettlingly, the only other species collected at this locality was Dineutusemarginatus, the species stated to be most similar to that of Dineutusamazonicus. Hopefully in the future the type may be rediscovered or this enigmatic species recollected and its relationship with Dineutusemarginatus clarified.The first author recently visited the type locality in an attempt to recollect this species, but was unsuccessful. The locality, Saline River, a large mud bottom river, also had present Taxon classificationAnimaliaColeopteraGyrinidaeGyrinusamericanusDineutesmetallicusDineutesamericanus: Schaum 1848: 337, Dineutus (Cyclinus) metallicus: “America”.8Gyrinusamericanus Linnaeus, 1767: syntype (1 ♀ card mounted) “2 [white label typed black ink]// americanus //” examined online through the Linnaen Society of London’s Linnean’s Insect Collection.Dineutusmetallicus Aubé, 1838: lectotype, here designated (1 ♀ pinned) “MUSEUM PARIS/ CUBA/ M. De LA SAGRA 764-36 // green circle [underneath is 764/ 36 handwritten in black ink]// metallicus au // PARATYPE // LECTOTYPE //” deposited in the MNHN. Paralectotype (1 ♀ pinned missing right mesothoracic leg past the femur and entire right metathoracic leg) same data as previous except without Aubé’s handwriting label and with “PARALECTOTYPE //” deposited in the MNHN.BAHAMAS:Great Exuma: Simons Pt., “23.31.50 75.37.30”, 26.i.1980, leg. S.A. Teale (1 ex. KSEM); Mayaguana Island: 3.viii.1963, leg. C.M. Murvosh, BLT (1 ex. FSCA). CUBA: Holguín river near Biological Station of PN La Mensura, Piloto, 657 m, 11.v.2013, 20.48640N, 75.779134W, leg. A. Deler-Hernández (1 ex. NMPC). DOMINCAN REPUBLIC:La Altagracia: Nisibón, 3.v.1978, leg. R.E. Woodruff & G.B. Fairchild, (1 ex. FSCA); Monte Cristi: 5 km N Villa Elisa, 10–18.v.1985, leg. E. Giesbert (1 ex. FSCA). PUERTO RICO: Almirante Rd., “K.B.Y.”, 9.iii.1935, leg. J.G. Needham (1 ex. MSBA). U.S.A.:The Virgin Islands: St. Thomas, 27.ii.1925, WIBF 011217 (1 ex. WIBF).Male Fig. : Size: 8Female Fig. : Size: 8Dineutusamericanus is unique among all other species of Dineutus in North American in having an elongate oval body form  it should again be noted that Dineutusamericanus is a Caribbean endemic and its range should limit confusion with all other species except for Dineutuscarolinus which is also found in the Bahamas  ( U.S.A.) , through U.S.A.) , Isle de U.S.A.) , Jamaica U.S.A.) , Dominic U.S.A.) , Puerto  U.S.A.) , Antigua U.S.A.) , to Guad U.S.A.) .Lentic species (M. Fikáček pers. com.), also an accidental inhabitant of caves in Cuba .Dineutusamericanus due to a long persisting synonymy issue (see the discussion under Dineutusassimilis). Mistaken records of Dineutusamericanus include Dineutusamericanus is only found in the Caribbean and the Florida Keys .Taxon classificationAnimaliaColeopteraGyrinidaeLeConte, 1878DineutesangustusDineutesdiscolor: Dineutesdiscolorvar. angustus: Dineutus (Cyclinus) angustus: Dineutusangustus: U.S.A., Florida15Dineutusangustus LeConte, 1878: syntype (1♀ pinned) “Type/ 6095 // Fla. // Dineutusangustus/ Lec. //” deposited in the MCZ.PageBreakPageBreakU.S.A.:Florida: Alachua Co., 3.ii.1949, leg. B.W. Cooper (2 ex. FSCA); Columbia Co., O’Leno State Park, 12.ii.1966, leg. F.W. Mead (7 ex. FSCA); Florida: Hillsborough Co., “USF Riverfront”, 21.v.1975, leg. G. Cowden (1 ex. FSCA); Suwannee Co., Branford, 16.vii.1934, leg. J.D. Beamer (4 ex. KSEM).Male Fig. : Size: 9Female Fig. : Size: 9Dineutusangustus is unique among all other North American Dineutus in its small size, parallel sided, very narrowly elongate oval body form , it is only weakly developed. In Dineutusdiscolor females the elytra are regularly rounded to the sutural production, with an apicolateral sinuation present.The shape of the apices of the female elytra of Fig. . U.S.A., Southern Georgia, and Eastern Alabama to northern Florida , then eventually accepting it as a species distinct from Dineutusdiscolor CyclinusassimilisGyrinusamericanus: Fabiricus 1775: 235 misidentified], [Cyclousamericanus: Dejean 1833: 58 misidentified], Dineutesassimilis: Dineutusamericanus: Dineutusassimilis: Dineutesamericanus: Dineutesassimilis: Dineutesamericanus: Dineutesassimilis: Dineutesamericanus: Zimmermann 1917: 137 misidentified], Dineutesassimilis: Dineutesamericanus: Leng 1920: 82 misidentified], Dineutus (Cyclinus) assimilis: Dineutus (Cyclous) americanus: Dineutusamericanus: Dineutusassimilis: Dineutusamericanus: Dineutusassimilis: Dineutus (Cyclinus) assimilis: Hatch 1930: 18, Dineutusassimilis: Dineutusamericanus:  Kirby 1837: 78, // Type/ 6093 // Dineutuscarolinus/ Lec. // LECTOTYPE/ Dineutuscarolinus/ Desig. R.P. Withington III/ 1998 //” deposited in MCZ.Dineutuscarolinusmutchleri Ochs, 1924: holotype  “Nassau, Bahamas, V-VI-1917/Wm. M. Mann Collector//Amer. Mus. Nat. Hist., Dept. Invert. Zool., No.28070/HOLOTYPE/DineutuscarolinusLeC.subsp.mutchleri OchsType ! ♂/Dineutuscarolinus LeConte 1868. Det: L. Cook 2005” AMNH type catalogue No. 433.PageBreakPageBreakBAHAMAS:Eleuthera Island: Rainbow Bay, 4.vii.1989, leg. D.B. & R.W. Wiley (1 ex. FSCA); Rainbow Bay, 21-28.iv.1984, leg. J.R. Wiley (6 ex. FSCA); Grand Bahamas Island: Freeport, 21.xii.1984, leg. S. Dunkle (4 ex. FSCA); Great Exuma: Simons Pt., “23.31.50-75.47.30”, 13.i.1980, leg. S.A. Teale (1 ex. KSEM); same as previous except: 21.i.1980 (1 ex. KSEM); same as previous except: 26.i.1980 (3 ex. KSEM); New Providence: 1.viii.1959, leg. J.B. Rearle (1 ex. FSCA); South Bimini: 14.vi.1967, leg. B.K. Dozier (2 ex. FSCA). U.S.A.:Arkansas: Washington Co., Devil’s Den State Park, pond, 6.viii.1975, leg. D. Huggins, SEMC 1054952 (1 ex. KSEM); Florida: Alachua Co., 10.ii.1949, leg. S.B. Mansell (5 ex. FSCA); same as previous except: 19.ii.1949, leg. B.W. Cooper (1 ex. FSCA); same as previous except: 8.iv.1949, leg. B.W. Cooper (2 ex. FSCA); same as previous except: 8.iv.1949, leg. E.H. McConkey (7 ex. FSCA); same as previous except: 19.iv.1949, leg. W.L. Jennings (1 ex. FSCA); same as previous except: 17.ii.1950, leg. O.G. Fogle (1 ex. FSCA); same as previous except: 15.iv.1950, leg. E.W. Michelson (1 ex. FSCA); same as previous except: 18.iv.1951, leg. J.E. Brogdan (1 ex. FSCA); same as previous except: x.1960, leg. S. Cabler (1 ex. FSCA); same as previous except: 4.ix.1989, leg. M.L. May (1 ex. FSCA); Gainesville, 20.iii.1987, leg. Willis, ACC.76-77; ACC.79-83; ACC.86; ACC.88 (9 ex. FSCA); Gainesville, 21.iii.1978, leg. L.R. Davis Jr., (2 ex. FSCA); same as previous except: 5.v.1978, leg. M.C. Thomas (1 ex. FSCA); same as previous except: 11.v.1978 (1 ex. FSCA); same as previous except: 2.vi.1978 (1 ex. FSCA); same as previous except: 18.iv.1983, leg. N. Hastettle (1 ex. FSCA); same as previous except: 5.vi.1983, leg. L.R. Davis Jr. (1 ex. FSCA); 5.vi.1959, leg. H.V. Weems Jr., taken at light (1 ex. FSCA); Gainesville, Beville Hts., 5.vii.1980, leg. L.A. Stange, Blacklight trap (1 ex. FSCA); NW Gainesville, 27.iii.1974, leg. J.B. Heppner, at blacklight (7 ex. FSCA); Gainesville, 3517 NW 10th Ave., 1.vi.1993, leg. R.E. Woodruff, Blacklight trap (8 ex. FSCA); 2 mi NW Gainesville, 20.iv.1974, leg. J.B. Heppner, blacklight (4 ex. FSCA); 6 mi SW Gainesville, 4.xi.1974, leg. L.R. Davis Jr., BLT (1 ex. FSCA); same as previous except: 5.xi.1974 (2 ex. FSCA); same as previous except:17.xi.1974 (1 ex. FSCA); same as previous except: 19.xi.1974 (2 ex. FSCA); Bainsville, 24.iii.1983, leg. C. Blare (1 ex. FSCA); Hatchet Creek, 25.vii.1975, leg. J.B. Heppner (3 ex. FSCA); O’Leno State Park, 8.viii.1997, leg. J. Cicero (3 ex. FSCA); Hogtown Creek, 28.vi.1975, leg. J.B. Heppner (1 ex. FSCA); Clay Co., Hibernia, 7.viii.1939, leg. J.D. Beamer (1 ex. KSEM); Collier Co., Copeland, 27.iv.1972, leg. H. Flaschka (1 ex. FSCA); Naples, 27.iv.1984, leg. R.A. Belmont, u.v. blacklight trap (1 ex. FSCA); Naples, 13.v.1984, leg. R.A. Belmont (4 ex. FSCA); Naples, 15.xii.1985, leg. R.S. Miller (1 ex. MTEC); Columbia Co., O’Leno State Park, 12.ii.1966, leg. F.W. Mead (1 ex. FSCA); O’Leno State Park,11.xii.1954, leg. C.N. Patton (1 ex. FSCA); Dade Co., nr Everglades Nat. Prk., fresh water, 7.v.1955, leg. D.K. Caldwell, K13 (8 ex. FSCA); Dade Co., Camp Mahachee, nr. Matheson Hammock, 27.iv.1983, leg. M.C. Thomas & L. Parker, Blacklight trap (2 ex. FSCA); Homestead, 28.v.1958, leg. D.O. Wolfenbarer, Blacklight trap (1 ex. FSCA); 25 m W Miami, 23.vii.1934, leg. P. McKinstry (1 ex. KSEM); 25 m W Miami, 23.vii.1934, leg. M.E. Griffith (1 ex. KSEM); Ross-Castello Hammock, 1.v.1968, leg. R.H. Arnett, Blacklight trap (1 ex. PageBreakFSCA); Miami Springs,15.vi.1961, leg. C.E. White (1 ex. FSCA); Dixie Co., Horseshoe Beach, 28.vii.1985, leg. P. Van Mierop, pond (1 ex. FSCA); Escambia Co., Pensacola, 17.v.1960, leg. R.E. Woodruff, col. At light (1 ex. FSCA); Gadsden Co., Rocky Comfort Creek, 4 mi S Hwy 268,13.v.1980, leg. G.B. Wibmer, uv light (1 ex. FSCA); Gulf Co., St. Joseph T.H. Stone Memorial State Park, 14.vi.1969, leg. H.V. Weems Jr. (1 ex. FSCA); Henderson Co., Fletcher, 10.vii.1979, leg. L.L. Lampert, U.V. Light (1 ex. FSCA); Hernando Co., Weekiwachee Spring, 3.vi.1954, leg. W.C. Sloan, Sta.4 (2 ex. FSCA); Highlands Co., Archbold Biol. Sta., 7.iv.1975, leg. L.L. Lampert, UVL (1 ex. FSCA); same as previous except: 18.xi.1982, leg. L.L. Lampert Jr., UVL (1 ex. FSCA); same as previous except: 19.iv.1976, leg. L.L. Lampert Jr. (1 ex. FSCA); same as previous except: 23.vi.1988, leg. K.E.M. Galley, at blacklight SE tract (2 ex. FSCA); same as previous except: 19.iii.1968, leg. C.E. White, at blacklight trap (2 ex. FSCA); same as previous except: 10.ii.1993, leg. M.J. Rothschild (1 ex. FSCA); Highlands Co., Highlands Hammock State. Prk., 9-10.viii.1983, leg. K.W. Vick, Blacklight trap (1 ex. FSCA); same as previous except: 11.viii.1983 (1 ex. FSCA); Hillsborough Co., Hillsborough RI St. Pk., 9-10.viii.1983, leg. K.W. Vick, Blacklight trap (5 ex. FSCA); Plant City, 20.vi.1926, leg. C. O. Bare (1 ex. KSEM); Indian River Co., nr. Vero Beach, 12.iv.1983, leg. K. Hibbard (3 ex. FSCA); Lake Co., 26.iv., leg. E.M. Davis, (3 ex. FSCA); Leon Co., Springhill Rd., nr. Airport, 16.x.1980, leg. B. Lenczerski (1 ex. FSCA); Liberty Co., Yellow Creek SE of Telogia, 5.ix.1990, leg. F.N. Young, #3435 (1 ex. FSCA); same as previous except: 7.x.1992, #3503 (1 ex. FSCA); Torreya State Park, 16.v.1970, leg. H. Greenbaum, blacklight/sheet (1 ex. FSCA); Marion Co., 1-75 & Rte. 44, 12.iii.1988, leg. L.R. Davis Jr. & M. L. Benoit, at light (1 ex. FSCA); Village of Rainbow Springs, 3-7.vii.1982, leg. M.C. Thomas (2 ex. FSCA); Ocala, 5.viii.1975, leg. T. Rogers (1 ex. FSCA); Big Pine Key, 15.iii.1947, leg. L.D. Beamer (1 ex. KSEM); Okaloosa Co., 3 mi S. of Holt Log Lake Bridge, 4.x.1966, leg. P.A. Thomas (3 ex. FSCA); Palm Beach Co., 28.xi.1947, leg. McRae (1 ex. FSCA); Palm Beach Co., 3 mi N Bell Grande, 13.xii.1985, leg. R.S. Miller (2 ex. MTEC); Saint Lucie Co., White City,1.iv.1983, leg. K. Hibbard (2 ex. FSCA); U.S.A.: Georgia: Okefenokee Swamp, 30.vii.1934, leg. E. Griffith (2 ex. KSEM); same as previous except: 8.iii.1934, leg. P.A. McKinstry (1 ex. KSEM); Decantur Co., 1 mi W Recovery, 18.viii.1953, leg. F.N. Young, #986 (2 ex. FSCA); Kansas: Labette Co., Altamont, 5 mi E, Labette Creek, 22.vi.1974, SEMC 1054951 (1 ex. KSEM); Louisiana: St. John the Baptist, Edgard, 6.iii.1973, leg. V. Brou (2 ex. FSCA); same as previous except: 9.iii.1973 (1 ex. FSCA); same as previous except: 11.iii.1973 (2 ex. FSCA); same as previous except: 30.iii.1973 (1 ex. FSCA); same as previous except: 14.iv.1973 (2 ex. FSCA); 19.iv.1973 (1 ex. FSCA); same as previous except: 15.vi.1973 (2 ex. FSCA); same as previous except:13.vii.1973 (1 ex. FSCA); East Baton Rouge, Baton Rouge,19.x.1929, leg. H.A.S. (1 ex. MTEC); same as previous except: 31.vii.1961, leg. G.N. Ross (1 ex. FSCA); Madison, Tallulah, 7.vii.1930, leg. H. Mills (1 ex. MTEC); Maryland: Worcester Co., Pocomoke City, 22.ix.1984, leg. C.L. Staines Jr. (1 ex. FSCA); North Carolina: Carteret Co., Walker Mill Pond, 15.iii.1990, leg. J.B. Sullivan (1 ex. FSCA); Craven Co., North Harlowe, 18.vii.1990, leg. J.B. Sullivan (1 PageBreakex. FSCA); Jackson Co., Balsam, 2.v.1965, leg. W. Rosenberg (1 ex. FSCA); Oklahoma: Payne Co., nr Lake Carl Blackwell, 16.viii.1976 (1 ex. FSCA); Texas: Colorado Co., 3.iv.1922, leg. G. Wiley, “U of X Lot 1108” (3 ex. KSEM); Colorado Co., 18.v.1922, leg. G. Wiley (1 ex. KSEM); Montgomery Co., Woodlands, 2.vi.1979, leg. J.E. Wappes (3 ex. FSCA); same as previous except: 3.v.1980 (1 ex. FSCA); Walker Co., “Strawn”, 7.iii.1952, leg. T. Pyburn, “Green Branch” (1 ex. FSCA); Virginia: Middlesex Co., Warner, 13.x.1983, leg. C.L. Staines Jr. (1 ex. FSCA).Male Fig. : Size: 9Female Fig. : Size: 8Dineutuscarolinus is unique among North American Dineutus in having both sexes elongate oval and the elytra with a distinct lateral marginal depression, the elytral apices regularly rounded with serration and irregularities present, males with the profermoral sub-apicoventral tooth small and often atop a short carina, the male mesotarsal claws with the ventral margin rounded, and the unique shape of the aedeagus. The species most similar to Dineutuscarolinus are Dineutusemarginatus, Dineutussolitarius, and Dineutusamericanus.PageBreakPageBreakDineutuscarolinus can be separated from Dineutusemarginatus by the elytra apices being more narrowly rounded with serrations and/or irregularities present. The presence of serrations, however, can be variable. In some individuals it is somewhat evident at the sutural margin, but others lack serrations entirely, having only roughened irregularities. The microreticulation of the elytra of Dineutuscarolinus tends to be much more coarse laterally and the medial disk of the elytra often lacks reticulation, whereas Dineutusemarginatus tends to have fine microreticulation covering the entire elytra. Although not as reliable, the ventral coloration differs between the two species. In Dineutuscarolinus the entire venter tends to be more reddish brown whereas it is regularly black in Dineutusemarginatus. The dorsal coloration of the two species is very similar.Both sexes of Dineutuscarolinus can fairly easily be separated from Dineutusemarginatus by the profemoral sub-apicoventral tooth small atop a profemoral carina, rather than large and triangular. Also, in Dineutuscarolinus the mesotarsal claws have the ventral margins rounded, rather than straight as in Dineutusemarginatus. The aedeagus is the best way to identify Dineutuscarolinus. The median lobe of Dineutuscarolinus is regularly narrowed for much its length, until the apical 1/3 where it is more strongly narrowed, but not strongly acuminate as in Dineutusemarginatus. Females of Dineutuscarolinus are more difficult to separate from Dineutusemarginatus. The best way to distinguish them aside from the more narrowly rounded elytral apices with serrations and/or irregularities in Dineutuscarolinus is the presence of an apicolateral sinuation in the elytra. This sinuation is nearly always present and well-developed in Dineutuscarolinus, although in some females it is sometimes weakly developed or absent. Dineutusemarginatus females nearly always have this sinuation absent, but at most only weakly developed.Males of Dineutuscarolinus of both sexes can be distinguished from Dineutussolitarius by more elongate oval body form, the pronotum more narrow with the lateral margins more narrowly angled basally to apically, and the elytral apices more narrowly rounded apically with serrations and irregularities present. Dineutuscarolinus of both sexes also have the lateral marginal depression of the elytra present, which is not evident in Dineutussolitarius. Males of Dineutuscarolinus differ from those of Dineutussolitarius by the mesotarsal claws with the ventral margin curved, unlike Dineutussolitarius that have the ventral margins straight. The aedeagus of Dineutuscarolinus is tapered but not acuminate, whereas that of Dineutussolitarius is acuminate. Females of Dineutuscarolinus can also be separated from those of Dineutussolitarius by the apices of the elytra laterally sinuate, whereas in Dineutussolitarius they are usually evenly rounded without an apicolateral sinuation, and if a sinuation is present, it is very weakly developed.Members of Dineutuscarolinus can be separated from Dineutusamericanus by the differences provided under the differential diagnosis for Dineutusamericanus.Fig. . Mainly known from the southeastern half of the United States  there is some variation, but not much from other populations of Dineutuscarolinus. A single male specimen examined from Texas has minor variation in the aedeagus from other mainland specimens .Having examined some specimens of ens Fig. , which mens Fig.  than othnus Fig.  from thenus Fig. . AlthougDineutuscarolinus from Florida and Georgia, that Dineutuscarolinusmutchleri are much more similar to these populations of Dineutuscarolinus than the Texas forms which he used as a comparison during description of Dineutuscarolinusmutchleri. It does appear that the Texas specimens are the most distinctive of Dineutuscarolinus populations, and the populations from the Caribbean formally named as a subspecies by Dineutuscarolinusmutchleri as a junior subjective synonym of Dineutuscarolinus.Taxon classificationAnimaliaColeopteraGyrinidaeGyrinusciliatusGyrinusvittatusCyclousvittatus: Dejean 1833: 58, Dineutesvittatus: Cyclousopacus Melsheimer, 1846: 29 // green disc [underneath is written in ink is 4117/ 33]// TYPE // LECTOTYPUS/ P. Brinck designavit 1955. // LECTOTYPE/ Dineutusdiscolor/ Desig. RP Withington III/ 1998 // LECTOTYPE [typed black ink]//” deposited in MNHN.U.S.A.:Alabama: Marion Co., Barnsville, 23.viii.1931, leg. R.H. Beamer (1 ex. KSEM); Monroe Co., 10 km W Bowles, 31°33.094'N, 86°59.956'W, 11.v.2006, leg. K.B. Miller (1 ex. MSBA); Arkansas: Washington Co., Lake Sequoyah, 7.x.1992, leg. S. Garner (3 ex. MTEC); Florida: Holmes Co., Sandy Creek nr. Ponce de Leon, 11.vi.1978, leg. F.N. Young, #2756 (1 ex. FSCA); Santa Rose Co., Holly Creek at Rd. 260, 6.x.1966, leg. P.A. Thomas, (1 ex. FSCA); Georgia: Jackson Co., Allen Creek, S. Gainesville, 20.viii.1981, leg. F.N. Young, #2887 (1 ex. FSCA); Indiana: Putnam Co., Deer Creek, Manhattan, 19.viii.1969, leg. D.S. White (3 ex. FSCA); Maine: Oxford Co., Paris, 8.vii.1949, leg. C.R. Frost, 2674/ CAF’49 (1 ex. FSCA); York Co., Limington, Saco River, RT.11 at steep falls, 22.vi.1976 (1 ex. FSCA); Maryland: Patapsco River, 30.iv.1935, leg. W.L. Jellison (11 ex. MTEC); Prince George’s Co., Riverdale, 10.i.1910 (1 ex. MTEC) Montgomery Co., 2 mi. E. Silver Spring, N.W. Branch, 20.vii.1951, leg. G.H. Nelson (4 ex. FSCA); Massachusetts: Hampshire Co., Amherst, 24.vii.1967, leg. A Lavallee, (1 ex. FSCA); Norfolk Co., Dedham, 10.vi.1921, leg. G.C. Wheeler (1 ex. FSCA); Missouri: Reynolds Co., Sutton’s Bluff, 9.ix.1978, leg. K. Jackson, in creek (11 ex. FSCA); New Jersey: Raritan River Survey I, ACC Station 3B, 2.vii.1957, leg. T. Dolan (2 ex. KSEM); Middlesex Co., Avenel, 24.iv.1926, leg. Siepman (1 ex. KSEM); New York: New York, 8.v.1892, leg. E.O. Southwick, E.O. Southwick collection (1 ex. MTEC); Greene Co., East Durham, 26.vii.1971, leg. S.E. Thewke (1 ex. FSCA); Westchester Co., White Plains, 1.vi.1924, leg. E.H.P. Squire, (8 ex. FSCA); same as previous except: 8.vi.1924 (1 ex. FSCA); same as previous except: 10.vi.1923 (1 ex. FSCA); North Carolina: Macon Co., small pond in WaPageBreakPageBreaktauga area n. Franklin, 26.vii.1986, leg. F.N. Young, #3118 (1 ex. FSCA); Moore Co., Mill Creek at Lake View, 7.ii.1966, leg. D.R. Paulson (1 ex. FSCA); Wake Co., 12.ix.1980, leg. R. Hollingsworth (3 ex. FSCA); Wake Co., Raleigh, leg. S.P. Whitney (4 ex. FSCA); same as previous except: 24.ix.1982, leg. R.H. Kenney (1 ex. FSCA); same as previous except: 12.ix.1984, leg. B.S. Bateman (1 ex. FSCA); same as previous except: 11.x.1984, leg. J.L. Williams (1 ex. FSCA); Wake Co., Raleigh, St. Road 1371, SW of Raleigh, 25.vii.1981, leg. S.P. Whitney, in stream (2 ex. FSCA); Rhode Island: Washington Co., Carolina, 24.ix.1970, leg. A. Lavallee (6 ex. FSCA); Kent Co., 1.ix.1969, leg. A. Lavallee (5 ex. FSCA); South Carolina: Aiken Co., Jackson, 4 mi NW at hwy 125 bridge, Holley Creek, 26.iii.1980, leg. D. Huggins, S. Hamilton, SEMC 1054961 (1 ex. KSEM); Tennessee: Cumberland Co., 8 mi S. Crossville, 26.vi.1962, leg. F.N. Young, #1968 (1 ex. FSCA); Maury Co., Colombia (1 ex. MTEC); Virginia: Albemarle Co., Charlottesville, 27.xi.1947, leg. H.H. Hobbs (1 ex. FSCA); West Virginia: Grant Co., 9 mi. SW Petersburg, 2.ix.1973, leg. J.B. Heppner (7 ex. FSCA).Male Fig. : Size: 1Female Fig. : Size: 1Dineutusdiscolor is unique among all North American species in the elongate oval and attenuate anteriorly body form, the elytra of both sexes with the apices rounded, with the sutural angle produced to a point with an apicolateral sinuation present, without serrations or irregularities present, a lightly colored venter, and males with the profemora with a small apicoventral tooth, and the form of the aedeagus GyrinusemarginatusDineutesamericanus: Dineutusemarginatus: Dineutesemarginatus: Dineutesemarginata Kellog 1905: 257, Dineutus (Cyclinus) emarginatus: Dineutus (Cyclinus) emarginatusfloridensis Ochs, 1929 // Dineutus ♀/ emarginatus (Say)/ Det. 1998 1999/ RP Withington III // emarginatus 5 // MCZ TYPE/ 34947 //.” As with all other R.P. Withington III designations for North America Dineutus, they were never published and are invalid, thus this specimen has absolutely no type status. As there is no question as to the identity of Dineutusemarginatus Say, no “exceptional need” exists for the designation of a neotype as per Article 75.3 of The Code ; Connecticut: New London Co., Ledyard, pond, 1.vi.1995, leg. K.B. Miller (2 ex. MSBA); Florida: Alachua Co., 2.ii.1949, leg. S.B. Mansell, (1 ex. FSCA); same as previous except: 23.iii.1949, leg. B.W. Cooper (1 ex. FSCA); same as previous except: 8.iv.1949, leg. E.H. McConkey (1 ex. FSCA); same as previous except: 30.iv.1949, leg. O.S. Russell (1 ex. FSCA); same as previous except: 15.iv.1950, leg. J.T. Darlington, (2 ex. FSCA); Alachua Co., Hatchet Creek, 25.vii.1975, leg. J.B. Heppner (4 ex. FSCA); Alachua Co., Gainesville, 6 mi. SW, 12.iii.1975, leg. L.R. Davis Jr., Blacklight trap (2 ex. FSCA); Clay Co., Camp Blanding Training Site, INSECT SURVEY SITE 11, Sand Pine Scrub, 29°55.599'N, 81°59.914'W, 24.ix.1999, leg. M. & M. Minno, Light trap (1 ex. FSCA); Hernando Co., Weekiwachee Spring, 5.iii.1953, leg. W.C. Sloan (1 ex. FSCA); Highlands Co., Archbold Biol. Sta., 7.iv.1975, leg. L.L. Lampert, UVL (2 ex. FSCA); Highlands Co., Highlands Hammock State. Prk., 11.iv.1964, leg. J. Waters (2 ex. FSCA); Collier Co., Immokalee, 23-28.iii.1960, leg. A.F. Wilson, Blacklight trap (1 ex. FSCA); Liberty Co., Yellow Creek SE of Telogia, 7.x.1992, leg. F.N. Young, #3503 (5 ex. FSCA); Walton Co., Eglin AFB., Range Rd. 205, 4.5 mi W. Hwy-331, 16.vi.1995, leg. P.E. Skelley et al., MV & blacklight (1 ex. FSCA); Georgia: Okefenokee Swamp, 1.iv.1969, leg. T.E. Rogers (1 ex. FSCA); Bibb Co., Macon, 20.v.1969 (1 ex. FSCA); Lowndes Co., 6.v.1963, leg. E.I. Hazard (1 ex. FSCA); Louisiana: West Feliciana, St. Francisville, 17.vi.1955 (1 ex. FSCA); Maryland: Charles Co., Allen’s Fresh, 15.viii.1984, leg. C.L. Staines Jr. (1 ex. FSCA); Prince George’s Co., Blue Pond, 29.ix.1949, leg. H.L. Dozier (1 ex. FSCA); Prince George’s Co., Greenbelt, 4.ix.1954, leg. H.L. Dozier, still pond in woods (1 ex. FSCA); Mississippi: Hancock Co., Turtleskin Creek, 25.iv.1965, leg. R. Hepburn (2 ex. FSCA); New Jersey: Bergen Co., Dumont Woods, 9.iv.1931, leg. C.L. Ragot, (5 ex. FSCA); New York: Queens Co., Corona, Long Island, 16.iv.1927, leg. C.L. Ragot (1 ex. FSCA); North Carolina: Wake Co., Raleigh, Yates Pond, 12.ix.1970, leg. L.L. Lampert (14 ex. FSCA); Ohio: Fairfield Co., Barnebey Center, 31.vii.1978, leg. D. Streett, sweeping net (4 ex. MTEC); Oklahoma: Latimer Co., 3.vii.1987, leg. K.E.M. Galley, at black light (2 ex. FSCA); South Carolina: Aiken Co., Jackson, 4 mi NW at hwy 125 bridge, Holley Creek, 26.iii.1980, leg. D. Huggins, S. Hamilton, SEMC 1054963 (1 ex. KSEM); Texas: Kinney Co., 17m NW Bracktville, 30.x.1997, leg. J.E. Wappes, MV/UV (1 ex. FSCA); La Salle Co., vic. Los Angeles, 11.ix.1993, leg. J.E. Wappes, (1 ex. FSCA); No locality info: “Station”, 8.v.1901, “Hatch Ex.”, (1 ex. MTEC).Male Fig. : Size: 8PageBreakFemale Fig. : Size: 8Dineutusemarginatus is unique among all other species of North American Dineutus in being elongate oval in body shape, having the elytral apices broadly rounded, without serrations and/or irregularities present apically, males with profemora possessing a large triangular sub-apicoventral tooth, and the shape of the aedeagus .habitats . In Flor present . This sp present . The firDineutusemarginatus was divided into two subspecies by Dineutusemarginatuss. str. and Dineutusemarginatusfloridensis Ochs, 1929. Dineutusemarginatusfloridensis from that of the typical form and on the difference in the number of setigerous punctures of the profemora, as well as some minor differences in the body form and elytral shape. This subspecies was also stated to be restricted to peninsular Florida  horni: Dineutus (Cyclous) hornii: Dineuteshorni: Dineutus (Cyclinus) hornii: Hatch 1930: 20, Dineutushornii: New York.45hornii ♂type # 4 C.H.R./LECTOTYPE Dineutushorni Desig: R.P. Withington III 1998/ Dineutushornii Roberts 1895 Det. L. Cook 2005” AMNH catalog no. 497.Syntype  “N.Y./Acc. 4858/Lectotype/ U.S.A.:Iowa: Boone Co., Ledges State Park, 2.v.1955, leg. M.D. Hoffman (2 ex. FSCA); Indiana: Brown Co., nr. Crooked Creek, 1.x.1977, leg. F.N. Young (1 ex. FSCA); Posey Co., Hovey Lake, 17.viii.1965, leg. C.E. White, Blacklight trap (1 ex. FSCA); Massachusetts: Middlesex Co., Hopkinton, 9.v.1915 (1 ex. FSCA); Michigan: Berrien Co., Harbert Dunes, 17.vii.1956, leg. G.H. Nelson, PageBreakPageBreakunder washup (1 ex. FSCA); Cheboygan Co., 29.vii.1928, leg. F.G. Batcher, (1 ex. KSEM); same as previous except: 25.vii1931, leg. H.B. Hungerford (1 ex. KSEM); Cheboygan Co., Douglas Lake, 29.vii.1927, leg. H.B. Hungerford (1 ex. KSEM); Cheboygan Co., Douglas Lake, Bessey Cr., 30.vi.1925, leg. H.B. Hungerford (1 ex. KSEM); New Hampshire: Carroll Co., “Summer” 1934, leg. N.H. Preble (4 ex. KSEM); New York: Broome Co., nr. Binghamton, 10.vii.1997, leg. K.B. Miller (8 ex. MSBA); Schuyler Co., Texas Hollow State Wildlife Area, 1.ix.1999, leg. K.B. Miller (2 ex. MSBA); Tompkins Co., Ringwood, 42°26'33"N, 76°21'47"W, 20.v.2000, leg. K.B. Miller (7 ex. MSBA); Saint Lawrence Co., Black Lake, 27.vii.1941, leg. E.J. Gerberg (1 ex. FSCA); Westchester Co., White Plains, 14.v.1922, leg. E.H.P. Squire (1 ex. FSCA); same as previous except: 30.v.1923 (1 ex. FSCA);Pennsylvania: Sussex Co., Peck’s Pond, 41°16'55.4"N, 75°15'18"W, 414 m, 29.v.2007, leg. P.A. Lenhart, swimming in pond (2 ex. MSBA); South Carolina: Aiken Co., Jackson, 4 mi NW at hwy 125 bridge, Holley Creek, 25.iii.1980, leg. D. Huggins, S. Hamilton, SEMC 1054964 (1 ex. KSEM); Wisconsin: Richland Co., lower WI River, State Wildlife Area, 2 mi W of Lone Rock, 4.x.1997, leg. A. Ramsdale, on surface of lentic pond, near margin, day (6 ex. MTEC).Putnam Co., Carmel, 2.viii.1923, leg. E.H.P. Squire (2 ex. FSCA); Male Fig. : Size: 9Female Fig. : Size: 1PageBreakDineutushornii can be distinguished from all other North American species of Dineutus in having the epipleura light yellow to orange, while still having a darkly colored venter (as opposed to similarly lightly colored as in Dineutusdiscolor)  Fig. , and theor) Fig. . The speura Fig.  lightly Dineutushornii can be readily distinguished from both Dineutusassimilis and Dineutusnigrior in having the elytral apices rounded (rarely angled towards the suture) and without the sutural angle produced to a point .The spelling of the specific epithet Dineutushornii forms rafts during the daytime consisting of hundreds to thousands of individuals, which may be composed of multiple species Dineutus species, easily distinguished from all other New World Dineutus, by the elytral apices possessing a spine located between the sutural and apicolateral angles. Serrations and irregularities are also present, and the sutural angle is also produced into a short spine. The venter is usually more lightly colored from reddish to yellow.This is a very unique Dineutuslongimanusportoricensis offering some significant differences. For these reasons we have decided to retain the classification proposed by This species is endemic to the Caribbean and represents a bit of a population genetics and Caribbean biogeography problem. The species is currently divided into four subspecies, with each island of the Greater Antilles having its own subpsieces, with the two most unique subspecies being found at opposite ends of the species distribution (Cuba and Puerto Rico). The two subspecies occupying the middle area of the range (Jamaica and the Dominican Republic) are less distinct and seem to form a gradient between the morphologies of the two subspecies at the opposite ends. The aedeagi of three of the subspecies are very similar with only that of Dineutuslongimanus can be distinguished from all other North American species of Dineutus in having the elytral apices spinose with serrations and irregularities present. The subspecies can be separated by the following key:PageBreakTaxon classificationAnimaliaColeopteraGyrinidaeOchs, 1927Dineutus (Dineutus) longimanuscubensisDineutus (Rhombodineutus) longimanus: Dineutus (Cyclinus) longimanus: Dineutuslongimanuscubensis: Cuba, Santiago de Cuba.17None examined.CUBA:Holguín: Sierra de Nipe, 25km S Mayari, Pinares de Mayari, 650 m, 03.vii.1990, leg. M.A. Ivie (7 ex. WIBF); Sierra de Nipe, Rio Piloto, 4.ii.1967, leg. R. Bielawski & A. Riedel (1 ex. WIBF) same as previous except: 590 m, 07.vii.1990, leg. M.A. Ivie (7 ex. WIBF); Pinar del Rio: Sierra del Rosario, Rancho Mundito, 16.vi.1959, leg. M.W. Sanderson, C59-29 (1 ex. FSCA); Sierra del Rosario, ca. 15km S CincoPesos Rangel, 420 m, 29.vi.1990, leg. M.A. Ivie, (1 ex. WIBF).Male Fig. . Size: 1Female Fig. . Size: 1Dineutuslongimanuscubensis is unique among the other subspecies of Dineutuslongimanus in being smaller in size (10.8–12.9 mm) and having the metacoxae with numerous shallow punctures present and covering most of their surface. The subspecies most similar to Dineutuslongimanuscubensis is Dineutuslongimanusjamaicensis and can primarily be distinguished by the differences in dorsal punctation and the punctures of the metacoxae as provided by the indentification key.Fig. . Cuba  longimanusjamaicensisDineutuslongimanusjamaicensis: Dineutus (Rhombodineutus) longimanus: Dineutus (Cyclinus) longimanus: PageBreakBlue Mountains, Jamaica, near 4500 ft. MCZ Type No. 23058.4jamaicus/ ochs // Dineutuslongimanusssp.jamaicus/ Ochs/ 1937/ Type! // Dineutus longimanus/ jamaicus/ Ochs/ 1937/ type no. 23058 //” deposited in the MCZ.Holotype  “Blue Mts./ nr 4500 ft./ Aug. 13-20 // Jamaica/ 1934/ Darlington // 23058/ M.C.Z./ HoloType/ JAMAICA:St. Andrew Parish: Maryland, Mamme River, 1.viii.1985, leg. M. Barrett, in clear stream (3 ex. FSCA).Male Fig. . Size: 1Female Fig. . Size: 1PageBreakDineutuslongimanusjamaicensis is unique among the other subspecies of Dineutuslongimanus in being larger in size (12.05–13.3 mm) and elongate oval in shape without apicolateral sinuation, and having the metacoxae with numerous shallow punctures covering most of their surface. The subspecies most similar to Dineutuslongimanusjamaicensis is Dineutuslongimanuscubensis and can be distinguished by the differences in dorsal punctation and metacoxal punctation provided in the key.PageBreakFig. . Jamaica .Dineutuslongimanuscubensis not much is known about Dineutuslongimanusjamaicensis aside from its taxonomy. It is currently only known from Jamaica.Similar to Taxon classificationAnimaliaColeopteraGyrinidaeGyrinuslongimanusGyrinusexcisusDineuteslongimanus: Dineutuslongimanus: Dineutus (Cyclinus) longimanus: Dineutus (Dineutus) longimanus: Dineutuslongimanus: Dineutus (Rhombodineutus) longimanus: Dineutus (Cyclinus) longimanus: Saint-Domingue (= Hispaniola).25Gyrinuslongimanus Olivier, 1795: lectotype, here designated: (♂ pinned) “MUSEUM PARIS/ I. St. Domingue/ COLL. BOSC 1828 // Gyrinuslongimanus/ I. St. Domingue Oliv. // TYPE // LECTOTYPUS/ P. Brinck designavit 1955. // TYPE // LECTOTYPE //” deposited in the MNHN.DOMINICAN REPUBLIC:Pedernales Prov.: W of Pedernales, on rd to border with Haiti, 18.154° ‘-71.582°, 13.v.2010, leg. G.J. Svenson, sweeping in dry for. & sec. veg. (17 ex. MSBA); N of Pedernales, La Aguita, 18°09.172'N, 71°44.786'W, 188 m, 21.vii.1999, leg. M.A. Ivie, Guerrero, & Dominici (5 ex. WIBF); 1 km N of Banano, Rio Mulitos, 18°09.258'N, 71°45.384'W, 290 m, 17.vi.2005, leg. G. Nearns, (2 ex. FSCA).Male Fig. . Size: 1Female Fig. . Size: 1Dineutuslongimanuslongimanus is unique among other subspecies of Dineutuslongimanus in being elongate oval and broadened posteriorly in the male after basal half of elytra, and having the metacoxae with sparse but present punctation. The subspecies most similar to Dineutuslongimanuslongimanus is Dineutuslongimanusportoricensis but can be distinguished from Dineutuslongimanusportoricensis in being smaller in size (12.3–13.9 mm) and the aedeagus lacking a dorsal carina.Fig. . Haiti, Dominican Republic, .Dineutuslongimanus may be obscured due to imprecise identification of subspecies.Similar to other species not much is known about this species aside from its taxonomy. The extant of range of this and other subspecies of Gyrinuslongimanus states it is found in St. Domingue and was described from the cabinet of M. Bosc. A single specimen in the MNHN general collection has a label indicating both the aforementioned locality and being from Bosc’s collection, as well as a label in the handwriting of Olivier with the I.D. of Gyrinuslongimanus, therefore this specimen  longimanus: Dineutus (Dineutus) longimanusportoricensis: Dineutuslongimanusportoricensis: Dineutus (Rhombodineutus) longimanus: Dineutus (Cyclinus) longimanus: Puerto Rico, Aibonito.27DineutuslongimanusOliv.subsp.portoricensis Ochs 1924, Typus ♂” AMNH type catalogue No. 434.Holotype  “Aibonito, P. R., June 1-3, 1915/Amer.Mus.Nat.Hist., Dept. Invert. Zool. No. 28073/HOLOTYPE/PUERTO RICO: “Hwy-31, Km. 15.4 nr. PasoSecoJct.”, 122 m, 1.viii.1963, leg. P.J. Spangler, (4 ex. WIBF); Germán: Río Cain, at PR361, 1 rd. mi. N jct. PR396, N of San Germán, 18°07.062'N, 67°01.518'W, 103 m, 14.v.2009, leg. C.B. Barr, EMEC 654754, 654755, 654757 (3 ex. EMEC); Lares: Río Camuy, E off PR134 1.2 rd.mi. N jct. PR111, NE of Lares, 18°18.204'N, 66°49.445'W, 278 m, 16.v.2009, leg. W.D. Shepard, EMEC 654756, 654758, 654759, 654760 (4 ex. EMEC); Maunabo: Río Guayanés, at PR181 just S jct. PR182, N Patillas, 18°03.397'N, 65°59.004'W, 422 m, 9.v.2009, leg. C.B. Barr, EMEC 654749-654753 (5 ex. EMEC); San Patillas: trib. Río Grande de Patillas at PR184, Bosque Carite Charco Azul Rec. Center, 18°05.460'N, 66°02.150'W, 597 m, 10.v.2009, leg. C.B. Barr, EMEC 654746-654748 (3 ex. EMEC); Uatado: trib. Río Caonillas E off PR 612, 2.3 rd. mi. N jct. PR140, NE of Utuado, S Lago dos Bocas, 18°18.177'N, 66°38.708'W, 99 m, 17.v.2009, leg. C.B. Barr, EMEC 654738-654745 (8 ex. EMEC).Male Fig. . Size: 1PageBreakPageBreakreduced apicolaterally, apicolateral sinuation present and shallow, elytra with reticulation strong laterally and apically, producing a bronzy appearance, medial disc with reticulation more weakly impressed and composed of smaller transversely ovoid sculpticells along with very shallowly impressed punctation, striae mostly effaced by reticulation, if evident at all faintly apparent medially on disc, lateral marginal depression of elytra present and accompanied with a green sheen; profemora without sub-apicoventral tooth; protibiae club-shaped; metacoxae with a sparse covering of very shallow punctures that are almost indistinguishable over most their ventral face, laterally only present on posterior margin; venter lightly colored: reddish orange to yellow-orange.Female Fig. . Size: 1Dineutuslongimanusportoricensis can easily be distinguished from other subspecies of Dineutuslongimanus in being large in size (11.2–14.5 mm), elytral margin with a lateral green sheen, and most distinctly in the form of the aedeagus. The species most similar to Dineutuslongimanusportoricensis is Dineutuslongimanuslongimanus but can easily be distinguished from it in being larger in size with the lateral marginal depression having a green sheen, and having the aedeagus with a dorsal carina.Fig. . Puerto Rico . Historical records also indicate this is a lotic subspecies .Dineutuslongimanuslongimanus the true extant of its range is obscured due to imprecise identification of the subspecies.Not much is known about this species aside from its taxonomy, and similar to PageBreakTaxon classificationAnimaliaColeopteraGyrinidaeOchs, 1925stat. n.DineutustruncatusmexicanusDineutus (Dineutus) truncatusmexicanus: Dineutustruncatusmexicanus: Dineutus (Dineutus) truncatusmexicanus: Dineutus (Cyclinus) truncatusmexicanus: Dineutustruncatusmexicanus:  Ochs 1925: 13, Mexico.44Coleoptera)/ Nr. 10393/ Dineutes spec./ Mexico, Schl./ Zool. Mus. Berlin” [green label] // “Dineutestruncatus/ Sharp/ determ. Ahlwarth” // “subspecies/ mexicanus/ Type! Ochs 1924”, // “subsp. * / mexicanus/ Ochs/ Mexico.” // “HOLOTYPUS/ Dineutestruncatus/ ssp. mexicanus Ochs, 1925/ labelled by MNHUB 2012” // deposited in the ZMHB. Paratypes: (♀ specimen missing left protarsus): “10393” [white label]// “Hits.-Coll. (Coleoptera)/ Nr. 10393/ Dineutes spec./ Mexico, Schl./ Zool. Mus. Berlin” [green label]// “? PARATYPUS/ Dineutestruncatus/ ssp. mexicanus Ochs, 1925/ labelled by MNHUB 2012” [red label]//; (♀ specimen): “4” // “85373” // “Mochtlan/ Guerrero/ Baron” // “Coll./ Harford”, white label “B.C.A. Col. I. 2./ Dineutes/ truncatus,/ Sharp.” // “Dineutestruncatus/ Sharp/ determ. Ahlwarth” [red label]// “PARATYPUS/ Dineutestruncatus/ ssp. mexicanus Ochs, 1925/ labelled by MNHUB 2012” [red label]//; (♂ specimen): “Mexico/ J.Flohr G.” [white label]// “94618” // “Hist.-Coll. (Coleoptera)/ Nr. 94618/ Dineutestruncatus Sharp/ Mixco, Juquila, Coll. Flohr/ Zool. Mus. Berlin/” [green label]// “truncatus/ Sh” [white label]// “? PARATYPUS/ Dineutestruncatus/ ssp. mexicanus Ochs, 1925/ labelled by MNHUB 2012” [red label]//;  “94618” // “Mexico/ J.Flohr G.” // “Hist.-Coll. (Coleoptera)/ Nr. 94618/ Dineutestruncatus Sharp/ Mexico, Juquila, Coll. Flohr/ Zool. Mus. Berlin” [green label]// “? PARATYPUS/ Dineutestruncatus/ ssp. mexicanus Ochs, 1925/ labelled by MNHUB 2012” [red label]//; (♂ specimen headless): “Juquila/ 15” //, “94618” // “Mexico, J.Flohr G.” [green label]// “Hist.-Coll. (Coleoptera)/ Nr. 94618/ Dineutestruncatus Sharp/ Mexico, Juguila, Coll. Flohr/ Zool. Mus. Berlin” [green label]// “PARATYPUS/ Dineutestruncatus/ ssp. mexicanus Ochs, 1925/ labelled by MNHUB 2012” [red label]// (6: ZMHB).Holotype (♂ with aedeagus dissected onto card point): “10393” [white label] // “Mexico Schl.”  // “Hist.-Coll. ; Chalatenango: San Jose del Sacare, 15.iii.1927, leg. R.A. Stirton (2 ex. KSEM); Tamanique: 1000 m, 8.xii.1972, leg. S. & L. Steinhauser (5 ex. FSCA); same as previous except: 3.vii.1972, leg. S. & L. Steinhauser (4 ex. FSCA). GUATEMALA:Zacapa: Sierra de los Minas, “El Naranjo”, S slope below San Lorenzo Mine, 15.07329 -89.68481, 1600-1700m, 21-24.v.2010, leg. P. Skelley, oak forest at light (1 ex. FSCA). HONDURAS: “nr Progreso”, Mico Quemado Mts, 6.xii.1958, leg. J.G. Matthysse, (2 ex. MSBA). MEXICO:Guerrero: Malinaltepec, Aserradero, 1500m, 2.xi.2000, leg. F. Pacheco, 24-8 (1 ex. IEXA); México: Villa Guerrero, Porfirio Díaz, Las Puentes, 14.iv.1990, leg. R. Arce, 7-4 (1 ex. IEXA); Michoacán: Chinicuila, Sierra de Coalcomán, La Nuez, Cañada El Colorín, , 15.ix.2003, leg. R. Novelo (2 ex. IEXA); same as previous except:16.ii.2005, leg. Gómex y Novelo, (2 ex. IEXA); Nayarit: 7mi N. Tetitlan, 14.vi.1962, leg. D.H. Janzen, EMEC 204752; 204756; 204853; 204856; 204866; 204894 (6 ex. EMEC); 8 mi SE San Blas, 27.vi.1967, leg. A.R. Hardy, (2 ex. UCRC); Oaxaca: San Juan Bautista Cuicatlán, Río La Concepción, 2.iv.1989 (4 ex. IEXA); km 84 carr 175 Oaxaca-Tuxtepec, 13.vi.1992, leg. R. Novelo (1 ex. IEXA); San José Independencia, Cerro el Vidrio, 1900 m, 25.v.2004, leg. G. Nogueira, (1 ex. IEXA); Veracruz: 6.vii.1965, leg. G.N. Ross, (2 ex. FSCA).Male Fig. : Size: 1Female Fig. : Size: 1PageBreakDineutusmexicanus is unique among all other North American Dineutus in having truncate elytra, with the lateral angle distinct, apicolateral sinuation weakly present, blunt serrations and irregularities present apically, males with a small acute profemoral sub-apicoventral tooth, and in the form of the aedeagus . The elytral truncature of Dineutusmexicanus differs in form having the apicolateral margin of the eyltra weakly sinuate, the lateral angle distinct, and the striae being more evident than those of Dineutustruncatus, especially in the males. There are also differences in body form discussed in the differential diagnosis section of Dineutustruncatus.gus Fig. . The speDineutusmexicanus can further be separated from Dineutustruncatus by the form of the protarsi .Dineutusmexicanus to full species status was based on the noticeable and significant differences between the aedeagi of Dineutustruncatus and Dineutusmexicanus as well as the external characters discussed in the differential diagnosis section for Dineutustruncatus. These external characters include the protarsi, mesotarsal claws, and the elytral truncature, all found to be reliable indicators of species boundaries in North American Dineutus. The holotype . Dineutustruncatus from Honduras, which Dineutusmexicanus. Specimens of Dineutusmexicanus for this study were also found in El Salvador, from several localities representing the southern-most confirmed record of Dineutusmexicanus. The western-most records for Dineutusmexicanus from this study are from Nayarit, Mexico, 8 miles southeast of San Blas. Confirmed specimens of Dineutusmexicanus are recorded from numerous records between these east and west localities including Guatemala, and the Mexican states of Veracruz, Oaxaca, and Guerrero. It is unclear how far north the range of Dineutusmexicanus extends in Central America and the Isthmus of Tehuanatepec. Based on the limited range data  nigrior: Dineutus (Cyclous) nigrior: Dineutus (Cyclinus) nigrior: Hatch 1930: 20. Dineutesnigrior: Dineutus (Cyclinus) nigrior: Dineutusnigrior: PageBreakUSA, Vermont.34nigrior ♂ type # 1 C.H.R./LECTOTYPE Dineutusnigrior Desig: R.P. Withington III 1998/ Dineutusnigrior Roberts 1895 Det : L. Cook 2005” AMNH type catalogue no. 498.Syntype  “Bengtn. Co., Vt./Acc.4858/ LECTOTYPE/ U.S.A.:Delaware: Sussex Co., Milsboro, 13.v.1973, leg. T.E. Rogers (1 ex. FSCA); Florida: Alachua Co., Gainesville, 27.vi.1961, leg. R.F. Bussey (1 ex. FSCA); Liberty Co., Torreya State Park, 25.v.1981, leg. J.R. Watts, at U.V. (1 ex. FSCA); Indiana: Crawford Co., Grantsburg, 18.vii.1965, leg. D. Eckert, Blacklight trap (1 ex. FSCA); Maryland: Prince George’s Co., College Park, 16.vi.1948, leg. B.K. Detler, in pond (1 ex. FSCA); Prince George’s CO., Blue Pond, 29.ix.1949, leg. H.L. Dozier, (1 ex. FSCA); Massachusetts: Suffolk Co, Forest Hills, 18.iv.1919 (1 ex. FSCA); Michigan: Allegan Co., State Game Area, 17.vii.1986, leg. J.A. Shuey (1 ex. MTEC); Cheboygan Co., Douglas Lake, 30.vii.1927, leg. H.B. Hungerford (1 ex. KSEM); same as previous except: “Mud L”, 31.vii.1923 (1 ex. KSEM); Washtenaw Co., “118 8h”, 24.iv.1921, leg. M.H. Hatch (1 ex. FSCA); Minnesota: Clearwater Co., Elk Springs, Itasca State Park, 12.viii.1965, leg. J.S. Nordin, attracted to U.V. (2 ex. FSCA); same as previous except: 7.vii.1965 (1 ex. FSCA); Morner Co., nr. Grand Meadow, roadside park, 18.viii.1965, leg. R.H. Arnett, in dammed pond (2 ex. FSCA); Missouri: Wayne Co., 3.2 mi WSW of Patterson Co. Rd. 332, deciduous Ozark forest and old field flora, 4.vii.1988, leg. H.M. Webber, at U.V. light (1 ex. FSCA); New Jersey: Cumberland Co., “Dividing Ck. Hansey Creek Rd.”, edge of salt marshes, 30.ix.1989, leg. D. Schloeitzer, at UV light (1 ex. FSCA); New York: Schuyler Co., Texas Hollow State Wildlife Area, 1.ix.1999, leg. K.B. Miller (1 ex. MSBA); Westchester Co., White Plains, 5.ix.1922, leg. E.H.P. Squire (1 ex. FSCA); same as previous except: 3.viii.1923 (2 ex. FSCA); same as previous except: 19.v.1923 (1 ex. FSCA); same as previous except: 30.v.1923 (1 ex. FSCA); same as previous except: 10.iii.1923 (1 ex. FSCA); same as previous except: 18.x.1924 (2 ex. FSCA); same as previous except: 12.iv.1925 (1 ex. FSCA); same as previous except: 19.v.1925 (1 ex. FSCA); Westchester Co., Montrose, 4.vii.1932, leg. C.L. Ragot (1 ex. FSCA); Pennsylvania: Sullivan Co., Picketts Glen St. Pk., 5.vii.1960, leg. G.W. Byers (2 ex. KSEM); Virginia: Giles Co., Mt. Lake Biol. Stat., 30.vi.1968, leg. H. Greenbaum (1 ex. FSCA); Wisconsin: Douglas Co., State Hunting Grounds, “T44N.R12W.Sec.11”, 23.vi.1999, leg. A Ramsdale, black light in barrens (1 ex. MTEC).PageBreakPageBreakcal 1/4, shortly rounded apically, in lateral view apex of median lobe strongly curved dorsally, parameres strongly curved in lateral view after basal 1/3.Male Fig. : Size: 1Female Fig. : Size: 1Dineutus in the extremely large size and assymetrical nature of the male mesotarsal claws  than males of both Dineutusassimilis and Dineutushornii. Dineutusnigrior males differ from males of Dineutushornii in having the sutural angle of the elytral apices produced into a point, and the venter of Dineutusnigrior is much more darkly colored than that of Dineutushornii, with the epipleura being similarly colored as the thoracic ventrites. Males of Dineutusnigrior can be distinguished from both Dineutusassimilis and Dineutushornii in having the mesotarsal claws markedly asymmetrical  than those of Dineutusassimilis and Dineutushornii, but unlike the case in the males, females of each of these three species have the sutural angles of the elytra produced into a point. However, the shape of the apices differs between them. In females of Dineutusnigrior the apices of the elytra are regularly rounded, and this situation is most different from Dineutushornii where the apices are generally angled towards the sutural production. Dineutusnigrior females can be separated from both Dineutusassimilis and from Dineutushornii in having the distolateral protibial margin produced, similar to the condition in males, but more weakly expanded.The females of Fig. . Extreme southeastern Canada from Manitoba to Nova Scotia  productus: USA, Texas.17Dineutus productus Roberts 1895 Det: L. Cook 2005” AMNH type Catologue 496.Syntype (♂ pinned) “Tex./Acc. 4858/Type productus, ♂type # 2, C.H.R./U.S.A.:Kansas: Bourbon Co., Ft. Scott, ca. 2 mi NE, Marmaton River, “T25S R25Esec 20 NW 1/4”, 4.viii.1976, leg. S. Hamilton, T. Oldham, SEMC 10549560 (1 ex. KSEM); Elk Co., Elk River at Elk Falls, 37.374416 -96.184123, 278m, 22.vi.2014, leg. C. Maier, C. Faris, S. Baca, G.Gustafson, GTG062214B (5 ex. GTGC), Elk River S. of Longton, 37.36960 -96.078735, 262m, 22.vi.2014, leg. C. Maier, C. Faris, S. Baca, G.Gustafson, GTG062214A (6 ex. GTGC); Greenwood Co., Lapland, 4mi S Fall River, east branch, 13.ix.1974, leg. D. Huggins, SEMC 1054959 (1 ex. KSEM); Lyon Co., Lyon Co.-Greenwood Co. line, Verdigiris River, “T21S R10E sec 36 SE 1/4”, 16.vii.1976, leg. S. Hamilton, SEMC 1054955, SEMC 1054957 (2 ex. KSEM); Morris Co., Council Grove Lake, outflows and groves, 13.vi.1974, leg. T. Edmonds, SEMC 1054958 (1 ex. KSEM); Texas: “Sequin”, 26.vi.1938, leg. D.W. Craik (2 ex. KSEM).Male Fig. : Size: 9Female Fig. : Size: 9Dineutusproductus can be distinguished from all other North American Dineutus in males having the profemora with a small sub-apicoventral tooth, accompanied by a series of denticles that extend proximad, with each denticle being associated with a posterior setigerous puncture of the profemora, elongate mesotarsal claws of equal size, with straight ventral margins  and for these specimens differences between the male secondary sexual characters as well as differences in the elytra allowed for unambiguous identification. The serration of the elytral apices differs between these two species. In Dineutusproductus the apices of the elytra only have irregularities present, at most having round bumps that resemble highly reduced serration, while in Dineutusserrulatusanalis the serration is present as distinct and fine points.orm Fig. , and beiDineutusproductus can easily be distinguished from those of Dineutusserrulatusanalis in that the profemoral sub-apicoventral tooth is small and accompanied by a series of denticles that extend proximad, with each denticle being associated with a posterior setigerous puncture of the profemora, in Dineutusserrulatusanalis there is a profemoral sub-apicoventral tooth as normal, but no accompanying series of denticles. This character appears unique to Dineutusproductus among all of the North American Dineutus species. The mesotarsal claws also differ greatly between these two species. Dineutusproductus males have the mesotarsal claws elongate with their ventral margins straight . The aedeagus is by far the most definite way to separate the two species. The aedeagus of Dineutusproductus ; Texas: Bosque Co. [Clifton]  indicate the species was collected from slow moving, cool, mud bottomed streams, that were fairly wide. , Mexico .PageBreakDineutusproductus appears to be an uncommonly collected species and the reason for this is not exactly clear. Most species found in the United States are uncommon due to a narrow range of endemism (e.g. Dineutusrobertsi and Dineutusangustus), but material examined in this study, as well as records from the literature, suggest the range of this species is not as narrow as the previously mentioned species. Dineutusproductus was originally described from Texas by Dineutusproductus, finding them to belong to other species. Dineutusproductus from outside of Texas actually belonged to other species upon his examination. In the same paper Dineutusproductus, confirming that the range of Dineutusproductus extends at least that far northward. This adds credence to Dineutusproductus within the MNHN, in order to confirm Dineutusproductus was not listed as a species of Dineutus found in North and South Carolina by Dineutusproductus (1949) matchs our own, therefore we accept his record for the species from Nuevo Leon, Mexico as representing the southern-most extreme for the range. As mentioned above, given the new Kansas records for the species and the habitat photos of the Sangamon River available online, we accept Material examined for this study from Kansas , was undoubtedly Dineutusproductus only mentioned having examined a few specimens . RecentTaxon classificationAnimaliaColeopteraGyrinidaeLeng, 1911DineutesrobertsiDineutus (Dineutus) robertsi: Ochs 1926: 138, Dineutusrobertsi: Dineutus (Protodineutus) robertsi: Dineutus (Cyclinus) robertsi: Dineutusrobertsi: U.S.A., Georgia: “West Branch War Woman Creek, Rabun Co., Ga., in the mountains, at an elevation of about 2,000 feet.”.PageBreak59Not examined, but specimens collected from the type locality.PageBreakU.S.A.:Georgia: Clayton Co., Warwoman Wldf Mgmt A, Tuckaluge Cr., 34.90155°N 83.30015°W, 533 m, 11.vii.2012, leg. K.B. Miller, KBM11071201 (31 ex. MSBA); Warwoman Cr., 34.89843°N 83.27512°W, 11.vii.2012, leg. K.B. Miller, KBM11071202 (8 ex. MSBA); Cleveland Co., Chattahoochee R., 34.72111°N, 83.74807°W, 12.vii.2012, leg. K.B. Miller, KBM12071202 (11 ex. MSBA); South Carolina: Moutain Rest Co., Sumter Ntl. For., 34.85292°N 83.14336°W, 12.vii.2012, leg. K.B. Miller, KBM11071203 (9 ex. MSBA).th elytral stria with large shallow punctures present; profemora without sub-apicoventral tooth; protibiae club-shaped; anterior mesotarsal claw .This species is easily distinguished from all other North American species of Dineutusrobertsi is Dineutusciliatus. Dineutusrobertsi differs from Dineutusciliatus in having the antennal club narrow and parallel sided, with the ultimate segment elongate and pointed apically, as opposed to having the flagellum being thicker and rounder with the ultimate segment rounded. Dineutusrobertsi also has the 8th elytral stria with punctures evident laterally as opposed to having them absent or indistinct as in Dineutusciliatus. The males of Dineutusrobertsi can further be distinguished from Dineutusciliatus in having the anterior mesotarsal claw  which is broader and more parallel sided. In lateral view the median lobe of Dineutusrobertsi  analis: Ochs 1926: 1377, Dineutusserrulatusanalis: Dineutusanalis:  Régimbart 1883: 416, U.S.A., Texas41Lectotype, here designated  “Texas // MUSEUM PARIS/ COLL MAURICE REGIMBART/ 1908 // LECTOTYPUS/ P. Brinck designavit 1955. // TYPE // LECTOTYPE //” deposited in the MNHN. Paralectotype  “Louisiana // MUSEUM PARIS/ COLL MAURICE REGIMBART/ 1908 // PARALECTOTYPE //” (1 ex. MNHN).U.S.A.:Arkansas: Washington Co., Lake Sequoyah, 7.x.1992, leg. S. Garner (1 ex. MTEC); Florida: Bradford Co., 3.ii.1949, leg. B.W. Cooper (1 ex. FSCA); Highlands Co., Highlands Hammock State. Prk., 15.iii.1974, leg. R.E. Beer (1 ex. KSEM); Liberty Co., Yellow Creek SE of Telogia, 7.x.1992, leg. F.N. Young, #3503 (12 ex. FSCA); Suwannee Co., Branford, 31.vii.1930, leg. P.W. Oman (1 ex. KSEM); Kansas: Elk Co., Longton, 1 mi S, 1 mi E, Elk River, “T31S”, 2.viii.1977, leg. S. Hamilton, SEMC 1057036 (1 ex. KSEM); Labette Co., Altamont, 5 mi E, Labette Creek, 22.vi.1974, SEMC 1056921, 1056919 (2 ex. KSEM); Montgomery Co., Caney, 25.vi.1991, leg. D. Miller, (1 ex. MTEC); Montgomery Co., Havana, ca. 2 mi N, Coon Creek, 24.vii.1974, leg. T. Edmonds, SEMC 1057032 (1 ex. KSEM); Montgomery Co., Drum Creek, US-160, 23.vii1974, leg. T. Edmonds, SEMC 1057034 (1 ex. KSEM) Sedwick Co., Goddard, 2.5 mi N, 5 mi E, creek, 17.vii.1975, leg. S. Matthies, SEMC 1057030 (1 ex. KSEM); Wilson Co., Altoon, 3.4 mi S, 3.5 mi E Chetopa Creek, “T29S R17E sec 31 NW 1/4”, 5.viii.1977, leg. S. Hamilton, T. Oldham, SEMC 1057019-1057020 (2 ex. KSEM); Wilson Co., Roper, 0.25 mi W, Buffalo Creek, “T27S R15E sec 35, 5.viii.1977, leg. S. Hamilton, T. Oldham, SEMC 1056998 (1 ex. KSEM); Mississippi: Hancock Co., Devil’s Swamp, 7.v.1965, leg. H.R. Hepburn (3 ex. KSEM); Hancock Co., Asley, 8.iii.1966, leg. H.R. Hepburn, (1 ex. KSEM); Tennessee: McNairy Co., 8 mi S.W. Ramer, 6.viii.1975 (4 ex. FSCA); Texas: Montgomery Co., The Woodlands, 10-18.vi.1977, leg. J.E. Wappes (1 ex. FSCA); Victoria Co., Victoria, Musang Creek, 8.ii.1932, leg. L.D. Tuthill (4 ex. KSEM).Male Fig. : Size: 9Female Fig. : Size: 1Dineutusserrulatusanalis is unique among all other North American Dineutus species in belong elongate oval and attenuated anteriorly, with elytral apices having apicolateral sinuations in both sexes, flatly rounded elytral apices, often with the sutural angle produced to a point, and with serration present, males with the profemora with a sub-apicoventral tooth, and in the form of the male aedeagus. The species most similar to Dineutusserrulatusanalis is Dineutusproductus. Dineutusserrulatusanalis can be separated from Dineutusproductus by the differential diagnosis given for Dineutusproductus.Dineutusserrulatusanalis and Dineutusserrulatusserrulatus can primarily be done using the differences in the key listed above.Distinguishing between Fig. . Southeastern United States  also show unique variation in the parameres  serrulatus: Dineutusserrulatusserrulatus: Dineutusserrulatus: U.S.A., “middle states” , but according to 117Dineutusserrulatus Lec. //” deposited in MCZ.Lectotype ; same as previous except: 29.iv.1950, leg. T.G. Stewart (1 ex. FSCA); Hatchet Creek, 25.v.1985, leg. D.W. Johnson, water (1 ex. FSCA); Hogtown Creek, 28.vi.1976, leg. J.B. Heppner (6 ex. FSCA); Gainesville, 14.iii.1963, leg. R.E. Woodruff, in blacklight trap (1 ex. FSCA); Bradford Co., 3.ii.1949, leg. B.W. Cooper, (2 ex. FSCA); same as previous except: 16.vii.1934, leg. J.D. Beamer (1 ex. KSEM); Columbia Co., O’Leno State Park,12.ii.1966, leg. F.W. Mead (17 ex. FSCA); same as previous except: 11.xii.1954, leg. C.N. Patton (1 ex. FSCA); Dade Co., iii.1954, leg. L.N. Bell, (1 ex. FSCA); Cutler, 26.xi.1960, leg. D.R. Paulson, (3 ex. FSCA); Canal at Pinecrest, 29.xii.1982, leg. F.N. Young, #2977 (1 ex. FSCA); Hernando Co., WeekiPageBreakwachee Spring, “Sta.4”, 3.vi.1953, leg. W.C. Sloan, (19 ex. FSCA); same as previous except: 3.vi.1954 (18 ex. FSCA); Highlands Co., Archbold Biol. Sta., 7.vi.1975, leg. L.L. Lampert (4 ex. FSCA); same as previous except: 2.iv.1979, leg. L.L. Lampert PageBreakJr. (2 ex. FSCA); Highlands Hammock State. Prk., 3.v.1974, leg. J.B. Heppner, at (UV) blacklight (9 ex. FSCA); same as previous except: 15.iii.1974, leg. R.E. Beer (1 ex. KSEM); Hillsborough Co., Morris Bridge Rd., 5.vii.1975, leg. S. Janisch (1 ex. FSCA); same as previous except: 4.vii.1977, leg. Boyd (1 ex. FSCA); “U.S.F Golf Course”, 21.v.1975, leg. “R.H” (1 ex. FSCA); “U.S.F. Campus”, 26.vi.1972 (1 ex. FSCA); same a previous except: 8.v.1979, leg. “S.T.” (1 ex. FSCA); Levy Co., 6.v.1950, leg. S.R. Young, (2 ex. FSCA); Okaloosa Co., 3mi S. of Holt Log Lake Bridge, 4.x.1966, leg. P.A. Thomas (9 ex. FSCA); Pasco Co., Crystal Springs, vii.1972 (1 ex. FSCA); same a previous except: 5.i.1975, leg. M. Lopez (1 ex. FSCA); Crystal Springs, Hill City, 5.i.1975, leg. J. Ward (1 ex. FSCA); Crystal Springs, “Hillshore”, 5.i.1975, leg. Diemer, (1 ex. FSCA); Polk Co., Mulberry, 24.vii.1972 (1 ex. FSCA); Seminole Co., 5.iv.1941, leg. M.J. Westfall Jr. (1 ex. FSCA); Taylor Co., Esconfina R. at US 98, 31.v.1987, leg. F.N. Young, #3189 (5 ex. FSCA); Volusia Co., Daytona Beach, 18.iv.1960, leg. R.E. Woodruff (1 ex. FSCA).Male Fig. : Size: 9Female Fig. : Size: 9PageBreakDineutusserrulatusserrulatus is unique among all other North American Dineutus in being elongate oval and attenuated anteriorly, having the elytral apices flatly rounded with serration present apically near the suture, both sexes with apicolateral sinuation present, being deeply sinuate in the males, males with a large and highly acute sub-apicoventral profemoral tooth, and in the form of the aedeagus. The species most similar to Dineutusserrulatusserrulatus is Dineutuscarolinus. Both Dineutusserrulatusserrulatus and Dineutuscarolinus have the elytral apices with serrations and or irregularities present apically. Dineutusserrulatusserrulatus of both sexes can be distinguished fairly easily from Dineutuscarolinus in the color of the venter. The venter of Dineutusserrulatusserrulatus is more lightly colored  solitarius: Dineutussolitarius: Dineutus (Cyclinus) solitarius: Dineutussolitarius: Mexico, Veracruz87solitarius // TYPE // LECTOTYPE //” deposited in the MNHN.Lectotype, here designated  “MUSEUM PARIS/ VERA-CRUZ/ 1833 // green disc [underneath is handwritten Veracruz/ 1883// in black ink]// COSTA RICA:Guanacaste: Santa Rosa N.P.,10°50.35'N, 85°37.07'W, 300 m, 6.vi.2008, leg. E. Nearns, I. Swift (2 ex. MSBA); 0.25km S Santa Rosa N.P., roadside pool, 15.vi.2003, leg. W.D. Shepard, EMEC 204684-204687; EMEC 204675 (5 ex. EMEC); La Pacifica nr Canas, 8.vi.1983, leg. J.E. Wappes, (1 ex. FSCA). EL SALVADOR:La Libertad: Hacienda Capolinas, 5 km NW Quezaltepeque, 455 m, 21.xii.1964, leg. M.E. Irwin (1 ex. UCRC). GUATEMALA:Jalapa: 4-7 km E. Jalapa, 12.vi.1991, leg. J.E. Wappes (1 ex. FSCA). HONDURAS:Comayagua: Malootal Minas de Oro, v.1932, leg. J.B. Edwards (3 ex. KSEM); Francisco Morazán: 4.5 km S.E. El Zamorano, 25.iv.1993, leg. I. Stange & R. Miller (1 ex. FSCA); La Paz: La Paz, 21.vii.1978, leg. V. Diaz, EMEC 204672 (1 ex. EMEC). MEXICO:Chiapas: 2.7mi W Colonia, Lazaro Cardenas, 6.viii.1965, leg. J.D. McCarty, EMEC 654699; EMEC 204761; EMEC 204769; EMEC 204777; EMEC 204801; EMEC 204807-204809 (8 ex. EMEC); 20 mi W of Cintalapa, 31.xii.1955, leg. J.C. Schaffner (2 ex. FSCA); Guerrero: Rincon, “kil.-256 S. MexCity”, 31.x.1936, leg. H.D. Thomas (1 ex. KSEM); Jalisco: UNAM Biol. Sta. Chamela, 61 m, 9.viii.1982, leg. C.W. & L. O’Brien & G. Wibmer, at light (1 ex. FSCA); Est. Biol. Chamela, at lites, 13-22.vii.1992, leg. J. Chemsak, EMEC 204753; EMEC 204881; EMEC 204897; EMEC 204925 (4 ex. EMEC); 20 mi N Puerto Vallerta, “200”, 29.viii.1971, leg. J. Cicero (1 ex. FSCA); Nayarit: 7 mi. N Tetitlan, 14.vi.1962, leg. D.H. Janzen, EMEC 204772-204773; EMEC 204786; EMEC 204800; EMEC 204805-204806; EMEC 204857-204858; EMEC 204917-204920 (11 ex. EMEC); El Pichon, 25.vi.1963 (1 ex. FSCA); Jesus Maria, 26.vi.1955, leg. B. Malkin, EMEC 204804 (1 ex. EMEC); Sierra Zapotan, 1300 m, iii.1943, leg. E. Paredes (3 ex. UCRC); 24 mi SE Tepic, 1045 m, 22.vi.1968, leg. A.R. Hardy, L. Espinosa, J.P. Abrayaya (2 ex. UCRC); 20.3 mi W Compostela, 60 m, 19.vi.1967, leg. A.R. Hardy (1 ex. UCRC); Nuevo León: 10km N Linares, mercury vapor lamp, 430 m, 23.iii.1991, leg. R. Brooks, R. Leschen, Coll. No. 58 (1 ex. KSEM); Oaxaca: 5 mi N La Ventosa, 4.vii.1970, leg. R.E. Beer & party (3 ex. KSEM); 80km N of Arriga,10.vi.1971, leg. S.R. & L.M. Steinhauser (2 ex. FSCA); Quintana Roo: 10.9km S Playa del Carmen,1.vii.1990, leg. M.C. Thomas, (1 ex. FSCA); Isla de Cozumel, SW side 2mi W Cedral, 8.x.1993, leg. C.B. Barr & W.D. Shepard, EMEC 654700 (1 ex. EMEC); San Luis Potosí: El Salto Falls, 15.vi.1956, leg. R.E. Beer & party (5 ex. KSEM); El Salto, 19.vi.1953, Univ. Kans. Mex. Expedition (2 ex. KSEM); same as previous except: 488 m, 24.viii.1954 (1 ex. KSEM); same as previous except: 381 m, 4.ix.1962, leg. Ordway & Marston, at light (1 ex. KSEM); Sinaloa: Culiaoan, 6 mi S, Black & White lights, 6.viii.1964, leg. J.A. Chemsak & J. Powell, EMEC 204803 (1 ex. EMEC); 5 mi N Mazatlan, at light, 11.x.1975, leg. J. Powell, J. Chemsak, T. Friedlander, EMEC 204778 (1 ex. EMEC); 15 mi SE Mazatlan, 27.vii.1973, leg. J. Chemsak, E.G. Linsleys & A.E. Michelbacher, EMEC 204779 (1 ex. EMEC); Veracruz: 15mi NW of Acayucan, 18.vi.1958, leg. J.C. Schaffner, (1 ex. FSCA); Palma Sola, “255 Pastizal”, 23.viii.1973, leg. G. Halffter & P. Reyes, Blacklight trap (1 ex. FSCA); 6mi SE Rinconada, 21.vi.1962, leg. D.H. Janzen, EMEC 204921 (1 ex. EMEC). NICARAGUA:Rivas: E of Lago de Apanás, 13°12.77'N, 86°58.06'W, 966 m, 12.vi.2005, leg. W.D. Shepard, EMEC 204676-204683 (8 ex. EMEC); Jinotega: roadside pool, Lago de Apanás area, N Jinotega, 13°12.8'N, 85°58.1'W, 966 m, 12.vi.2005, leg. C.B. Barr, EMEC 204673-204674 (2 ex. EMEC). U.S.A.:California: Riverside Co., Mecca, 15.viii.1924, EMEC 654698 (1 ex. EMEC); Texas: “Pinto”, 7.vii.1938, leg. D. W. Craik (1 ex. KSEM).Male Fig. : Size: 9Female Fig. : Size: 9PageBreakDineutussolitarius is unique among all other North American Dineutus in being smaller in size (9.1–10.4 mm), with a broadly oval body form  and California  have the punctures of the elytra much more shallowly and weakly impressed, making them much larger and “dimply” in appearance  show variation in body form. The outline of the body is much more broadly oval in these specimens. There is also a much greater dorsoventral convexity in the scutellar region, especially evident in lateral view. It should be noted that although there are these variations among populations, the aedeagi of males from each of these populations are not noticeably different or variable in any significant manner.There is some noticeable variation in the elytral sculpturing among populations of nce Fig. . This istus Fig. . These sDineutesmetallicus Aubé, the only specimen with a date and Aubé’s handwriting for the determination label was selected as the lectotype GyrinussublineatusDineutessublineatus: Dineutesinteger LeConte 1854: 221 // Dineutusinteger/ Webb Lec./ Copper Mines // sublineatus 2 //” deposited in MCZ.EL SALVADOR:Chalatenango: San Jose del Sacare, 15.iii.1927, leg. R.A. Stirton (2 ex. KSEM). GUATEMALA:Baja Verapaz: 15 km N Salama, 5.vi.1991, leg. J.E. Wappes (1 ex. FSCA). HONDURAS:Comayagua: Malootal Minas de Oro, v.1932, leg. J.B. Edwards (1 ex. KSEM). MEXICO:Aguascalientes: Sierra Fria ca. 40 mi SW Rinconde Romos, 2438 m, 11.iii.1953, leg. I.J. Centrall, #55 (2 ex. FSCA); Baja California Sur: Bahía Concepción, “Lanito”, 15 m, 16.iv.1968, leg. M.E. Irwin (1 ex. UCRC); Sierra Laguna, 17 air mi ENE Todos Santos, 1829 m, 12-18.xii.1979 EMEC 204906-204907 (2 ex. EMEC); Sierra Laguna, 17 mi ENE Todos Santos, 12-18.xii.1979, leg. J. Doyen, W. Tschinkel, EMEC 204770-204771; EMEC 204793-204799; EMC 204811-204815; EMEC 204817-204823; EMEC 204827-204849; EMEC 204860 (47 ex. EMEC); Arroya Posa ca. 10 mi W Loreto, 183 m, 6.vi.1978, leg. C.M. Murvosh & R.K. Allen, EMEC 654702-654710 (9 ex. EMEC); 9 mi WSW Loreto, Arroyo Las Parras, 207 m, 10.vii.2004, leg. W.D. Shepard, EMEC 204602-204619 (18 ex. EMEC); 9 mi SW Loreto, Arroyo Las Parras, 250 m, 20.vii.2004, leg. W.D. Shepard, EMEC 204620-204644 (25 ex. EMEC); 0.6mi S San Javier, 387 m, 20.vii.2004, leg. W.D. Shepard, EMEC 204668-204669 (2 ex. EMEC); Ram di Naran Rd., 10-28k W Rt 1, 28-31.viii.1994, leg. J.E. Wappes (1 ex. FSCA); 4.3 km E La Burrera, 550 m, 11-14.x.1978, leg. Dezier & Westcott, canyon-stream (1 ex. FSCA); Chihuahua: 3 mi NW Chihuahua, 20.viii.1952, leg. J.D. Lattin, S. Weitsman, EMEC 204861 (1 ex. EMEC); 15 mi E Cuauhtemoc, Black & White lights, 2012 m, 11.vii.1964, leg. J.A. Chemsak & J. Powell, EMEC 204916 (1 ex. EMEC); 13 mi E Cuauhtamoc, Black & White lights, 2012 m, 11.vii.1964, leg. J.A. Chemsak & J. Powell, EMEC 204825 (1 ex. EMEC); Hidalgo, 25 mi W Del Parral, Black & White lights, 2073 m, 15.vii.1964, leg. J.A. Chemsak & J. Powell, EMEC 204904 (1 ex. EMEC); Hidalgo, 25 mi W Parral, Black & White lights, 2073 m, 15.vii.1964, leg. J.A. Chemsak & J. Powell, EMEC 204824 (1 ex. EMEC); Chihuahua, 1524 m, 4.ix.1963, leg. H.V. Weems Jr., collected at light (1 ex. FSCA); Chiapas: El Zapotal, 2 mi S Tuxtla Gutierrez, 15.vii.1956, leg. J.W. MacSwain, D.D. Linsdale, EMEC 204888; EMEC 204892 (2 ex. EMEC); El Chorreodero, 600 m, 15.v.1991, leg. J.D. McCarty, EMEC 204645 (1 ex. EMEC); Simojovel, 1-16.viii.1958, leg. J.A. Chemsak, EMEC 204759; EMEC 204909 (2 ex. EMEC); Coahuila: 1 mi SE Saltillo, at blacklight, 23-26.ix.1976, leg. J.A. Chemsak & J.A. Powell, EMEC 204792 (1 ex. EMEC); Durango: Nombre de Dios, 25.vi.1952, leg. E.E. Gilbert, C.D. MacNeil, EMEC 204859; EMEC 204911-204915 (5 ex. EMEC); 6.3 mi N Nombre de Dios, 1829 m, 25.vi.1952, leg. R.F. Smith, EMEC 204910 (1 ex. EMEC); Guerrero: Mochitlan, Acahuizotla, Bosque tropical bajo caducifolio, 750 m, 11.vii.1986, leg. L. Delgado (1 ex. FSCA); Zumpango del Rio, 2.xi.1943, leg. E.K. Waering (1 ex. FSCA); Jalisco: Puerto Los Mazos, 9mi SW Autlan, 27.viii.1970, leg. M.S. & J.S. Wesbauer, EMEC 204776; EMEC 204780-204785 (7 ex. EMEC); 6 mi W Chapala, 30.vi.1963, leg. J. Doyen, EMEC 204790; EMEC 204787-204788 (3 ex. EMEC); PageBreakRio de Tepospisaloya, ca. 6 km N Union de Tula, 9.2 km W Tacotán, 20°03.86'N, 104°20.91'W, 381 m, 10.i.2005, leg. C.B. Barr, EMEC 654701 (1 ex. EMEC); México: NE of Temescaltepec, Canubi a Chichotla, 2027 m, 23.iv.2004, leg. W.D. PageBreakShepard, EMEC 204600-204601 (2 ex. EMEC); Michoacán: 26.7 km N La Huacana, 18.vii.1989, leg. R. Brooks, A. Roig, (1 ex. KSEM); Morelos: Alpuyeca, 3.vii.1951, leg. P.D. Hurd, EMEC 204757 (1 ex. EMEC); Nuevo León: 15 mi W Linares, 27.viii.1969, leg. J. Haddock, J.T. Doyen, EMEC 204774-204775 (2 ex. EMEC); 4 mi W of El Cercado, 6.vi.1951, leg. P.D. Hurd, EMEC 204758 (1 ex. EMEC); 4 mi S of Monterrey nr Siesta Motel, 6.vii.1963, leg. R.H. Arnett Jr., E.R. VanTassell, Lot No. V-56 (1 ex. FSCA); same as previous except: 7.vii.1963, Lot No. V-58 (8 ex. FSCA); 3.9 km NE Iturbide, ex: stream, 1410 m, 24.iii.1991, leg. Brooks, Leschen, #62 (1 ex. KSEM); 37 km SW Linares, 4.8 km S on Bosque Esquela Rd., ex:pool, 1545 m, 20.iii.1991, leg. Brooks, Leschen, #13 (1 ex. KSEM); 10 mi W of Cola del Caballo Falls, 24.xii.1972, leg. J.C. Schuster (2 ex. FSCA); Nayarit: 7mi N Tetitlan, 14.vi.1962, leg. D.H. Janzen, EMEC 204746-204751; EMEC 204754-204755; EMEC 204767; EMEC 204850-204852; EMEC 204854-204855; EMEC 204862-204865; EMEC 204869-204880; EMEC 204882-204883; EMEC 204885-204886; EMEC 204898; EMEC 204922-204924 (38 ex. EMEC); La Mesa de Nayar, 19.vii.1955, leg. B. Malkin, EMEC 204867-204868; EMEC 204887; EMEC 204889-204891; EMEC 204893; EMEC 204895-204896; EMEC 204899-204905; EMEC 204914 (16 ex. EMEC); Sierra de Zapotan, iii.1943, leg. E. Paredes, Pool in stream (3 ex. FSCA); Sierra Zapotan, 1300 m, iii.1943, leg. E. Paredes (2 ex. UCRC); 24 mi SE Tepic, 1045 m, 22.vi.1968, leg. A.R. Hardy, L. Espinosa, J.P. Abrayaya (1 ex. UCRC); Oaxaca: 4 mi W Tehuantepec, 21.vii.1952, leg. E.E. Gilbert, C.D. MacNeil, EMEC 204763-204766 (4 ex. EMEC); Oaxaca, ix.1957 (1 ex. FSCA); same as previous except: 28.ix.1957 (1 ex. FSCA); same as previous except: 29.ix.1957 (4 ex. FSCA); 33 mi W of Tehuantepec, 762-914 m, 22.viii.1963, leg. H.V. Weems Jr., in pool in mt. stream (12 ex. FSCA); Puebla: 11 mi SE Acatlan, 10.vii.1952, leg. E.E. Gilbert, C.D. MacNeil, EMEC 204760; EMEC 204762 (2 ex. EMEC); 45 mi N Acatan, 30.vii.1963, leg. J. Doyen, EMEC 204789; EMEC 204791 (2 ex. EMEC); 3 mi NW Petlalcingo, 1402 m, 29.viii.1972, leg. Byers & Thornhill (1 ex. KSEM); Sinaloa: 21 mi E Ville Union, Black & White lights, 91 m, 25.vii.1964, leg. J.A. Chemsak & J. Powell, EMEC 204816 (1 ex. EMEC); 36 mi N of Mazatlan, 18.xi.1955, leg. J.C. Schaffner (1 ex. FSCA); Sonora: 7 mi W Alamos, Blk- & White lights, 8.viii.1964, leg. J.A. Chemsak, J. Powell, EMEC 204810; EMEC 204826 (2 ex. EMEC); 5 km N Alamos, 6.viii.1998, leg. M.S. Caterino, EMEC 204768 (1 ex. EMEC); 7 mi SE Alamos, 27.xi.1970, leg. K. Stephan (1 ex. FSCA); nr Guicochi, 1768 m, 25.i.1972, leg. V. Roth (1 ex. FSCA); Veracruz: Laguna Verde, 30.iii.1975, leg. C. Halffter, P. Reyes, BLT (2 ex. FSCA). U.S.A.:Arizona: Cochise Co., SW Reg. Sta., 5 mi SW Portal, 4.viii.1961, leg. J.M. Linsley, EMEC 204884 (1 ex. EMEC);1 mi up CarrCyn R., 9.vii.1972, leg. J.M. Cicero (2 ex. FSCA); 6 mi E Bisbee, 17.vii.1972, leg. J.M. Cicero, (1 ex. FSCA); Skeleton Canyon, 24.viii.1962, leg. D. Weems (1 ex. FSCA); Skeleton Canyon, 1372-1524 m, 24.viii.1962, leg. H.V. Weems Jr. (1 ex. FSCA); Cave Creek Canyon, 11.vii.1984, UVL (1 ex. FSCA); Coronado Ntl. For., Idlewild cmpgd, 18.v.1990, leg. R.S. Miller (1 ex. MTEC); Huachuca Mtns, Bear Cr., rock PageBreakpools in strm, 31°22'24"N, 110°21'40"W, 26.iv.2000, leg. K.B. Miller, #2000-12 (1 ex. MSBA); Rucker Canyon, pools in strbed, 25.iv.2000, leg. K.B. Miller (1 ex. MSBA); Hidalgo Co., Skeleton Canyon, Peloncillo Mts., 1372-1524 m, 25.viii.1962, leg. H.V. Weems Jr., in stream (1 ex. FSCA); Pima Co., Tucson, v.1958, leg. L. Lenando (2 ex. MTEC); Tucson, 2.viii.1970, leg. K. Stephan (1 ex. FSCA); Tucson, Sabino Canyon, 29.v.1958, leg. L. Lenando (1 ex. MTEC); Mouth of Madera Canyon, 17.vi.1967, leg. B. Streit (7 ex. FSCA); Madera Canyon, 22.ix.1977, leg. R.S. Miller (1 ex. MTEC); Catalina Mts., 4.viii.1930, leg. L.K. Gloyd, 145 (4 ex. FSCA); Sabino Canyon, 22.viii.1968, leg. F. Hovore, 489-490 (2 ex. FSCA); Box Spring Canyon, 8.viii.1986, leg. R.S. Miller (1 ex. MTEC); same as previous except: 9.viii.1986 (1 ex. MTEC); same as previous except: 10.viii.1986 (1 ex. MTEC); Sta. Rita Exp. Range, 04.viii.1988, leg. S. Lajeunesse (1 ex. MTEC) same as previous except: leg. M.M. Hooten (1 ex. MTEC); Coronado Ntl. For., 6.ix.1938, leg. C.L. Hubbs family, 102b (1 ex. FSCA); Santa Catalina Mtns., Molino Canyon, 3.iii.1968 (5 ex. FSCA); same as previous except: 30.iii.1969 (1 ex. FSCA); Santa Cruz Co., Peña Blanca, 24.viii.1977, leg. R.S. Miller (2 ex. MTEC); same as previous except: 20.viii.1971, leg. J. Cicero (2 ex. FSCA); same as previous except: 16.vii.9172 (1 ex. FSCA); Peña Blanca Lake, 10.x.1990, leg. W.B. Warner (2 ex. FSCA); Peña Blanca Lake, 20.vii.1982, leg. G.H. Nelson, Ultraviolet light (2 ex. FSCA); Madera Canyon,15.vii.1972, leg. J. Cicero (2 ex. FSCA); Sycamore Canyon, 16.iv.1950, leg. R.R. Miller & H.E. Winn, M-50-40 (1 ex. FSCA); Mt. Hopkins, 27.vii.1992, leg. J.&M. Huether (1 ex. FSCA); Spring fed trib. to Peña Blanca Canyon, 17.iv.1950, leg. R.R. Miller & H.E. Winn, M50-41 (1 ex. FSCA); Santa Rita Mts., Gardner Canyon, PageBreak22.vi.1975, leg. K. Stephan (2 ex. FSCA); New Mexico: Hidalgo Co., Peloncillo Mtns., Clanton Canyon, pool in wash, 20.ix.2009, leg. A.B. Johnson et. al. (3 ex. MSBA); Texas: “Big Bend”, vii.1960, leg. D. Thornton (3 ex. FSCA); John Davis Co., Valentine, 13.vii.1927, leg. L.A. Anderson (2 ex. KSEM); Kerr Co., Kerrville, 2.vii.1938, leg. I. Norris (2 ex. FSCA).Male Fig. : Size: 1Female Fig. : Size: 1PageBreakPageBreakDineutussublineatus is unique among all North American Dineutus in being large in size, with a more or less regularly elongate oval body form, with all 9 elytral striae strongly evident, males with a small well developed and highly acute profemoral sub-apicoventral tooth, the form of the aedeagus . Other label data also indicate pools in steams. In the United States the second author has collected this species in pools in dry streambeds within canyons in southern Arizona.Lotic and lentic. In Oaxaca, Mexico, 43 mi w of Tehuantepec Dineutussublineatus. Females tend to be more evenly elongate regularly oval, while males have a greater dorsoventral convexity in the scutellar region  resulting in a steepness in the humeral region of the elytra and the posterolateral region of the pronotum. Males of Dineutussublineatus also have the lateral margin, just posterior to the humeral region of the elytra, slightly expanded. As mentioned earlier females also have a medial exspansion of abominal sternite VII, not seen the males.There is dimorphism in body form among the sexes of Dineutussublineatus. Without a male to unambiguously place the Guatemalan specimen as a different species, we considered it a variation of Dineutussublineatus, as it possessed the diagnostic females character of the medial expansion of abdominal sternite VII, thus far unique to Dineutussublineatus.This species exhibits a large amount of variation throughout its range, with noticeable variation in body form. A series of specimens from near Tehuanatepec, Oaxaca, Mexico, has the females noticeably smaller than the males, and much more parallel sided in appearance, as well as both sexes with the elytral apices very flatly rounded, nearly truncate in appearance. A single female specimen from Salama, Guatemala Fig.  (UCRC), Dineutussolitarius , ius Fig. . Other vDineutus.Even though there is a great deal of variability in these species in terms of body form, elytral apices, and elytral sculpturing, several characters are very stable. These include the strong development of the elytral striae in both sexes, in males the form of the aedeagus, and in females abomdinal sternite VII possessing a medial expansion. There is very minimal varation in the form of the male aedeagus, which is the most diagnostic character for species recognition within PageBreakTaxon classificationAnimaliaColeopteraGyrinidaeSharp, 1873DineutestruncatusDineutustruncatus: Dineutus (Dineutus) truncatus: Dineutustruncatus: Dineutus (Dineutus) truncatus: Dineutus (Cyclinus) truncatus: Dineutustruncatus: Chontales, Nicaragua, BMNH34Not examined.COSTA RICA:Alajuela: Zapote Upala, nr. Bijaqua, 20.x.1973, leg. F. Cordera EMEC 204671 (1 ex. EMEC); same as previous except: 10.ix.1973, leg. R. Ortiz, EMEC 204908 (1 ex. EMEC); Guanacaste: Rincon de la Vieja N.P., Quebrada Cataracta, 15.vi.2003, leg. W.D. Shepard, EMEC 204646-204667 (22 ex. EMEC); Puntarenas: Las Cruces Bio. Station, water tank, 1158 m, 19.vi.2003, leg. A.E.Z. Short, (2 ex. KSEM); Monte Verde, Rio Guacimal, 1420 m, 15.v.1989, leg. J. Ashe, R. Leschen, R. Brooks, Snow Entomol. Mus. Costa Rica Exped. #198 (1 ex. KSEM); 6 km S Sta. Elena, 6-7.vi.1983, leg. J.E. Wappes (1 ex. FSCA). PANAMA:Ngäbe-Buglé: nr. Soloy, 8°36.554'N, 82°07.814'W, 7.vi.2009, leg. Nearns, Lord, small stream (6 ex. MSBA).Male Fig. : Size: 1Female Fig. : Size: 1PageBreakPageBreakDineutustruncatus is unique among all other New World Dineutus in having the elytral apices truncate, with fine serration present apically, males with the ultimate protarsomeres . The aedeagus of this specimen is strange, even among the world Dineutus fauna, as discussed above. While the aedeagus does appear to be asymmetrical in the parameres, suggesting a malformation, the rest of the body is highly symmetrical, without any noticeable deformities. Other specimens encountered that were clearly aberrant in some way, had asymmetrical features in the body, usually the prothoracic legs. Given the distinct characters discussed we have included the specimen here without placing it among any of the known species. However, as we only have a single specimen, and given its very odd genitalia, we have decided not to formally describe this species due to lack of additional material. Other Dineutus specimens examined from western and north central Oaxaca (IEXA) belonged to Dineutusmexicanus. However, this specimen comes from a locality to the south separated by a mountain range, again suggesting it may indeed represent a species other than Dineutusmexicanus. Hopefully future collecting near Tapanatepec, Oaxaca, Mexico will allow placement of this enigmatic specimen.There are several characters that suggest this specimen represents a species distinct from Dineutusamazonicus Hatch, 1930 Arkansas, USADineutusamericanus  Bahamas, CarribeanDineutusangustus LeConte, 1878 SE USADineutusassimilis  SE Canada; most of USADineutuscarolinus LeConte, 1868 E USA, BahamasDineutusciliatus  E USADineutusdiscolor Aubé, 1838 SE Canada, E USAPageBreakDineutusemarginatus  E USADineutushornii Roberts, 1895 SE Canada, E USADineutuslongimanus  CarribeanDineutuslongimanuscubensis Ochs, 1927 CubaDineutuslongimanusjamaicensis Ochs, 1938 JamaicaDineutuslongimanuslongimanus  HispaniolaDineutuslongimanusportoricensis Ochs, 1924 Puerto RicoDineutusmexicanus Ochs, 1925 S Mexico to El SalvadorDineutusnigrior Roberts, 1895 SE Canada, E USADineutusproductus Roberts, 1895 Texas, Kansas, USA and NE MexicoDineutusrobertsi Leng, 1911 SE Appalachian mountains, USADineutusserrulatus LeConte, 1868 E USADineutusserrulatusanalis Régimbart, 1882 E USADineutusserrulatusserrulatus LeConte, 1868 SE USADineutussolitarius Aubé, 1838 SW USA to W Costa RicaDineutussublineatus  SW USA to NicaraguaDineutustruncatus Sharp, 1873 Nicaragua to W Panama