Front  C0X8B  angulated,  with  distinct  trochantin,  middle  coxal
cavities  widely  open  externally ;  metasternum  longer  than  the
first  ventral  segment  (as  in  all  the  following  tribes);  the  inter-
coxal  process  acute;  middle  tibiae  with  a  distinct  tubercle  on  tlie
outer  margin;  tarsi  not  elongated,  last  joint  large,  claws  not  fully
divaricated,  but  somewhat  movable  as  in  Cerambycidse  genuini.
The  last  ventral  segment  is  truncate  in  both  sexes,  but  more  so
in  the  9.
Three  groups  exist  in  our  fauna.
Legs  long,  the  front  pair  elongated  in  % ,  and  the  antennae  much  longer
than  the  bodjr ;

Prothorax  with  lateral  spines.  Mokohammi.
Prothorax  cylindrical.  Ptychodes.
Legs  equal,  not  elongated.  Goes.
Group  I. — Monohamml.
Several  species  of  Monohamnius  represent  this  group  in  various
parts  of  the  country ;  they  aflect  the  wood  of  pine  trees.     Tiie


320  COLEOPTERA  Of   NORTH   AMERICA.
gronp  is  easily  recognized  by  the  deeply  cbanuelled  vertex,  very
long  %  anteunse,  scape  with  an  apical  cicatrix,  long  slender  legs,
the  front  pair  mach  longer  in  the  % ;  the  lower  lobe  of  the  eyes
is  a  little  longer  than  wide.  The  prothorax  has  a  strong  lateral
spine.
The  last  ventral  segment  in  the  %  is  feebly,  in  the  ?  more
strongly,  truncate;  the  ventral  segments  are  nearly  equal  in  length.
Gronp  II. — Ptyohodes.
These  have  also  very  elongate  antennae,  and  slender  legs,  the
front  pair  elongated  in  the  % ;  the  vertex  is  deeply  and*narrowIy
channelled;  the  lower  lobe  of  the  eyes  is  broader  than  long.  The
first  and  5th  ventral  segments  are  longer  than  the  intermediate
ones,  the  last  is  feebly  truncate  in  the  % ,  but  more  strongly  in
the  9.     The  prothorax  is  cylindrical.
