Sharp  (Biol.  Cent.  Amer.  Coleoptera,  i.  pt.  2,  pp.  66  et  seq.)  into
a  number  of  genera,  of  which  two  occur  in  our  fauna:  Philhy-
drus, in  which  the  mesosternum  has  a  longitudinal  carina,  and
the  middle  and  hind  tarsi  6-jointed,  Eydrocombus,  with  the  meso-
sternnm  at  most  slightly  transversely  carinate,  and  the  middle  and
hind  tarsi  4-jointed.  The  latter  genus  contains  those  species
placed  in  the  division  Helochares  by  Dr.  Horn  (Proc.  Amer.
Phiios.  Soc.  xiii.,  1873,  p.  130).  Helochares  proper  has  not  yet
been  recognized  in  our  fauna..
Berosus  altus  Lee.  and  one  Mexican  species  form  the  genus
Derallus  Sharp  (loc.  cit.,  p.  77),  which  differs  from  Berosus  in
having  the  front  tibiae  broader  to  tip  and  not  slender.
Page  73. — Cyclonotum  estriatum  Sa?/ forms  the  type  of  Phse-
nonotum  Sharp  (loc.  cit.,  p.  97).  In  Cyclonotum  the  intercoxal
carina  is  formed  entirely  by  the  mesosternum,  in  Phaenonotuni
the  metasternum  is  prolonged  in  front  of  the  middle  cox®.  Proba-
bly other  species  will  enter  this  genus.
Page  165. — The  name  Helichus  must  be  replaced  by  Dryops.
Dr.  Sharp  states  that  the  characters  given  by  Erichson  for  the
.separation  of  these  genera  do  not  exist  (vide  Biol.  Cent.  Amer.
Coleoptera,  i.  pt.  2,  p.  119).
Page  193. — The  genera  of  Throscida;  indicate  two  tribes,  the
Lissomini,  represented  in  our  fauna  by  Drapetes,  and  Throscini
by  Throscus  and  Pactopus.  As  the  tribal  names  are  used  in  the
tables  (pp.  xxxii.,  xxxiv.),  they  are  mentioned  here  to  explain
their  absence  on  p.  193,  the  small  number  of  genera  not  seeming
to  require  tribal  division.
(533)


534  APPENDIX  I.
Page  210. — The  occurrence  of  additional  material  has  enabled
us  to  make  a  careful  dissection  of  Omethes  with  the  following
result : —

OMETHES  Lee.
