﻿408 
  REVISION 
  OF 
  THE 
  ELATERIDES 
  

  

  exposing 
  slightly 
  the 
  articulation; 
  in 
  the 
  Eucnemides 
  (except 
  Anelastes) 
  the 
  margin 
  is 
  re- 
  

   gular, 
  and 
  the 
  articulation 
  entirely 
  concealed; 
  the 
  abdomen 
  lias 
  only 
  five 
  ventral 
  seg- 
  

   ments, 
  except 
  in 
  Cebrio 
  and 
  an 
  allied 
  genus, 
  where 
  the 
  fifth 
  joint 
  is 
  truncate 
  and 
  the 
  sixth 
  

   becomes 
  prominent. 
  The 
  femora 
  articulate 
  at 
  the 
  apex 
  of 
  the 
  trochanters, 
  which 
  arc 
  thus 
  

   fulcrant; 
  the 
  tarsi 
  are 
  never 
  much 
  dilated, 
  occasionally 
  furnished 
  with 
  membraneous 
  lobes 
  

   beneath, 
  and 
  usually 
  pubescent; 
  the 
  fifth 
  joint 
  is 
  slender 
  with 
  two 
  equal 
  claws, 
  varying 
  in 
  

   form, 
  and 
  usually 
  with 
  a 
  small 
  intermediate 
  appendage 
  terminated 
  by 
  two 
  setse. 
  The 
  

   tibia? 
  are 
  usually 
  slender, 
  never 
  fossorial, 
  rarely 
  compressed; 
  in 
  one 
  genus, 
  allied 
  to 
  Ce- 
  

   brio, 
  a 
  tendency 
  to 
  the 
  fossorial 
  form 
  is 
  shown. 
  

  

  'Hie 
  mentum 
  is 
  small, 
  trapezoidal, 
  and 
  indexed; 
  the 
  base 
  of 
  the 
  maxilla? 
  exposed; 
  the 
  

   laller 
  have 
  two 
  distinct 
  lobes, 
  the 
  outer 
  one 
  is 
  never 
  palpiform; 
  the 
  last 
  joint 
  of 
  the 
  max- 
  

   illary 
  palpi 
  is 
  usually 
  dilated, 
  and 
  larger 
  than 
  the 
  preceding; 
  in 
  Tharops 
  and 
  Melasis, 
  

   however, 
  the 
  terminal 
  joint 
  is 
  oval 
  and 
  pointed, 
  and 
  not 
  much 
  larger 
  than 
  the 
  one 
  before 
  

   it; 
  in 
  Adrastus 
  alone, 
  of 
  the 
  true 
  Elaterides, 
  it 
  is 
  long 
  and 
  acuminate; 
  and, 
  finally, 
  in 
  the 
  

   Cebrionides 
  it 
  is 
  cylindrical 
  and 
  truncate; 
  the 
  labial 
  palpi 
  are 
  very 
  small 
  except 
  in 
  the 
  

   Cebrionides. 
  

  

  From 
  this 
  detail 
  of 
  characters, 
  we 
  would 
  at 
  first 
  be 
  inclined 
  to 
  select 
  for 
  the 
  definition 
  

   of 
  our 
  three 
  primary 
  groups, 
  (admitting 
  them 
  to 
  be 
  three 
  in 
  number,) 
  the 
  insertion 
  of 
  the 
  

   antennae, 
  and 
  the 
  structure 
  of 
  the 
  abdomen, 
  as 
  being 
  those 
  of 
  probably 
  the 
  greatest 
  value. 
  

   Genera 
  are 
  soon 
  found, 
  however, 
  in 
  which 
  all 
  the 
  other 
  characters 
  of 
  Cebrio 
  are 
  found, 
  

   and 
  which 
  have 
  the 
  abdomen 
  constructed 
  as 
  in 
  other 
  Elaterides; 
  the 
  form 
  of 
  the 
  mandi- 
  

   bles 
  is 
  obviously 
  a 
  character 
  of 
  too 
  little 
  value 
  for 
  a 
  primary 
  division; 
  we 
  are 
  thus 
  forced 
  

   to 
  divide 
  the 
  entire 
  family 
  into 
  two 
  great 
  groups: 
  Eucnemides, 
  having 
  the 
  antenna? 
  in- 
  

   serted 
  in 
  a 
  sinus, 
  and 
  somewhat 
  approximated, 
  and 
  the 
  clypcus 
  dilated 
  anteriorly; 
  Elaterides, 
  

   having 
  the 
  antennae 
  inserted 
  at 
  the 
  margin 
  of 
  the 
  eyes, 
  under 
  the 
  front, 
  which 
  is 
  not 
  dila- 
  

   ted 
  anteriorly, 
  and 
  not 
  narrowed 
  at 
  the 
  middle. 
  

  

  The 
  Eucnemides 
  contain 
  three 
  distinct 
  types: 
  Melasis, 
  with 
  the 
  small 
  acute 
  terminal 
  

   joint 
  to 
  the 
  maxillary 
  palpi, 
  the 
  imperfectly 
  protected 
  mouth, 
  and 
  the 
  hardly 
  approximated 
  

   antenna?; 
  Eucnemis, 
  with 
  moderately 
  approximate 
  antenna?, 
  and 
  convex 
  deflexed 
  front; 
  

   Cerophytum, 
  with 
  closely 
  approximate 
  antenna', 
  and 
  somewhat 
  gibbous 
  front. 
  

  

  The 
  Elaterides 
  divide 
  naturally 
  into 
  two 
  groups: 
  the 
  true 
  Elaterides, 
  with 
  small 
  re- 
  

   tracted 
  mandibles, 
  and 
  small 
  labial 
  palpi; 
  and 
  the 
  Cebrionides, 
  with 
  long 
  porrected 
  man- 
  

   dibles, 
  and 
  cylindrical 
  palpi, 
  all 
  of 
  which 
  are 
  moderately 
  elongated. 
  

  

  These 
  tribes, 
  with 
  the 
  exception 
  of 
  the 
  true 
  Elaterides, 
  arc 
  so 
  small, 
  that 
  their 
  resolu- 
  

   tion 
  into 
  genera 
  is 
  attended 
  with 
  no 
  difficulty: 
  it 
  is 
  very 
  different, 
  however, 
  with 
  that 
  

   large 
  and. 
  difficult 
  group, 
  nor 
  have 
  any 
  previous 
  attempts 
  to 
  arrange 
  its 
  contents 
  been 
  

   attended 
  with 
  any 
  success. 
  

  

  On 
  examining 
  the 
  other 
  groups, 
  with 
  a 
  view 
  to 
  ascertain 
  whether 
  any 
  light 
  could 
  be 
  

   gained 
  from 
  them, 
  I 
  found, 
  in 
  the 
  genuine 
  Eucnemides, 
  a 
  remarkable 
  correspondence 
  in 
  

   elongated 
  basal 
  joint 
  of 
  the 
  antenna^, 
  and' 
  the 
  absence 
  of 
  any 
  tooth 
  at. 
  the 
  internal 
  

   part 
  of 
  the 
  coxal 
  plates: 
  the 
  genus 
  Anelastes 
  makes 
  the 
  only 
  exception 
  to 
  this 
  latter 
  cha- 
  

   racter; 
  and 
  the 
  various 
  places 
  given 
  to 
  that 
  curious 
  genus 
  by 
  different 
  authors 
  sufficiently 
  

  

  