﻿Carabideous 
  fauna 
  of 
  Mexico, 
  269 
  

  

  The 
  description 
  above 
  given 
  of 
  the 
  northern 
  B. 
  ampli- 
  

   pemiis 
  will 
  apply 
  to 
  this 
  form 
  from 
  the 
  opposite 
  extremity 
  

   of 
  Mexico, 
  with 
  the 
  exception 
  that 
  the 
  elytra, 
  instead 
  of 
  

   having 
  a 
  large 
  number 
  of 
  piliferous 
  punctures 
  in 
  the 
  

   inter.vtices, 
  have 
  only 
  an 
  irregular 
  row 
  of 
  mostly 
  glabrous 
  

   punctures, 
  at 
  least 
  in 
  the 
  interstices 
  1 
  — 
  6 
  from 
  the 
  base 
  

   to 
  about 
  the 
  middle. 
  The 
  punctures 
  are 
  destitute 
  of 
  

   hairs 
  towards 
  the 
  base, 
  and 
  hence 
  the 
  elytra 
  are 
  more 
  

   glabrous 
  and 
  shining 
  ; 
  their 
  colour 
  also 
  is 
  generally 
  

   greener 
  than 
  in 
  B. 
  ainpJipejinis. 
  The 
  thorax 
  is 
  some- 
  

   what 
  elongate, 
  and 
  varies 
  in 
  outline, 
  as 
  in 
  the 
  other 
  

   species, 
  and 
  its 
  surface 
  is 
  densely 
  clothed 
  with 
  piligerous 
  

   punctures. 
  

  

  In 
  one 
  or 
  two 
  examples 
  of 
  the 
  series 
  before 
  me 
  the 
  

   interstitial 
  punctures 
  are 
  not 
  uniseriate, 
  but 
  irregularly 
  

   two 
  or 
  three 
  abreast 
  ; 
  these 
  form 
  transitions 
  to 
  B. 
  

   Tahasconus, 
  and 
  the 
  form 
  can 
  scarcely 
  be 
  considered 
  as 
  

   more 
  than 
  a 
  local 
  variety 
  of 
  that 
  species. 
  Transition 
  

   varieties 
  are, 
  however, 
  very 
  frequent 
  in 
  the 
  genus 
  

   Brachinus. 
  

  

  Brachinus 
  cognatus, 
  Chaud., 
  Monogr. 
  d. 
  Brachyn., 
  p. 
  64. 
  

  

  The 
  typical 
  form 
  of 
  B. 
  cognatus 
  in 
  Southern 
  and 
  East- 
  

   central 
  Mexico 
  has 
  short 
  convex 
  elytra, 
  with 
  strong 
  

   glossy 
  carinse 
  and 
  smooth 
  interstices 
  ; 
  the 
  whole 
  under 
  

   surface 
  being 
  pale 
  red, 
  like 
  the 
  head 
  and 
  thorax. 
  A 
  

   character 
  omitted 
  by 
  Chaudoir 
  is 
  the 
  absence 
  of 
  hairs 
  

   from 
  the 
  surface 
  of 
  the 
  thorax 
  and 
  elytra 
  ; 
  viewed 
  

   laterally, 
  no 
  trace 
  of 
  pilosity 
  is 
  visible. 
  The 
  following 
  

   variety 
  is 
  from 
  Northern 
  Mexico 
  ; 
  it 
  agrees 
  with 
  the 
  

   type 
  in 
  every 
  respect, 
  except 
  as 
  stated 
  in 
  the 
  following 
  

   diagnosis 
  : 
  — 
  

  

  Var. 
  cancellatus. 
  Elytra 
  longius 
  ovata, 
  convexa, 
  carinis 
  elevatis, 
  

   angustioribus 
  interstitiisque 
  transversim 
  impressis; 
  antenuis 
  

   articulo 
  4to 
  Sioque 
  basi 
  fuscis. 
  Long. 
  7 
  — 
  8 
  millim. 
  

  

  Hah. 
  Aguas 
  Calientes 
  City 
  ; 
  Villa 
  Lerdo, 
  in 
  Durango; 
  

   Chihuahua 
  City 
  (Hoge). 
  

  

  In 
  two 
  examples 
  only, 
  respectively 
  from 
  Lerdo 
  and 
  

   Chihuahua, 
  are 
  the 
  transverse 
  impressions 
  of 
  the 
  elytral 
  

   interstices 
  strongly 
  marked 
  ; 
  but 
  they 
  agree 
  with 
  the 
  

   others, 
  in 
  their 
  subelongate 
  form 
  and 
  other 
  characters, 
  

   from 
  Aguas 
  Calientes. 
  

  

  