﻿370 
  Mr. 
  C. 
  J. 
  Gahan 
  on 
  mimetic 
  resemblances 
  

  

  are 
  much 
  less 
  varied 
  in 
  their 
  markings. 
  It 
  would 
  seem 
  

   from 
  this 
  that 
  certain 
  species 
  of 
  Lema 
  had 
  departed 
  

   somewhat 
  from 
  the 
  style 
  of 
  marking 
  prevalent 
  in 
  their 
  

   genus 
  in 
  order 
  to 
  mimic 
  species 
  of 
  Diahrotica 
  living 
  in 
  

   the 
  same 
  localities. 
  This 
  view 
  is 
  all 
  the 
  more 
  reasonable 
  

   when 
  it 
  is 
  taken 
  into 
  account 
  that 
  the 
  shape 
  of 
  the 
  

   elytra 
  in 
  some 
  of 
  the 
  mimicking 
  Lemas 
  approximates 
  

   more 
  to 
  that 
  of 
  the 
  mimicked 
  Diabroticas 
  than 
  to 
  the 
  

   form 
  customary 
  in 
  their 
  own 
  genus. 
  There 
  are, 
  in 
  

   fact, 
  one 
  or 
  two 
  species 
  of 
  Le7na 
  with 
  their 
  elytra 
  so 
  

   shaped 
  and 
  coloured 
  that 
  one 
  might 
  almost 
  venture 
  to 
  

   predict 
  that 
  they 
  will 
  be 
  found 
  to 
  mimic 
  species 
  of 
  

   GalerucidcB. 
  

  

  Mr. 
  Bates 
  has 
  mentioned 
  some 
  cases 
  of 
  Longicorns 
  

   which 
  mimic 
  GalerucidcB. 
  One 
  of 
  these 
  is 
  Oxylymma 
  

   gihbicolUs, 
  Bates, 
  which, 
  he 
  says, 
  closely 
  resembles 
  a 
  

   species 
  of 
  Diahrotica. 
  

  

  Mr. 
  Jacoby, 
  without, 
  I 
  think, 
  suggesting 
  any 
  explana- 
  

   tion 
  of 
  the 
  facts, 
  has 
  recorded 
  that 
  mam^ 
  of 
  the 
  species 
  

   of 
  his 
  genus 
  Neohrotica 
  exhibit 
  most 
  striking 
  resem- 
  

   blances 
  to 
  species 
  of 
  the 
  closely-related 
  genus 
  Diahrotica. 
  

  

  There 
  are 
  a 
  few 
  species 
  of 
  other 
  allied 
  genera 
  which 
  

   also 
  resemble 
  species 
  of 
  Diahrotica. 
  Dircema 
  fraterna, 
  

   described 
  by 
  the 
  late 
  Mr. 
  Baly 
  and 
  originally 
  placed 
  by 
  

   him 
  in 
  Diahrotica, 
  has 
  a 
  most 
  deceptive 
  resemblance 
  to 
  

   Diahrotica 
  trij^lagiata, 
  a 
  species 
  from 
  the 
  same 
  locality. 
  

   This 
  example 
  is 
  all 
  the 
  more 
  remarkable, 
  because 
  D. 
  

   fraterna, 
  with 
  its 
  glabrous 
  and 
  highly 
  polished 
  elytra, 
  is 
  

   very 
  unlike 
  most 
  of 
  the 
  other 
  species 
  of 
  Dircema, 
  which 
  

   are 
  covered 
  with 
  a 
  kind 
  of 
  velvety 
  pubescence. 
  

  

  If 
  the 
  species 
  of 
  Diahrotica 
  are 
  not 
  favoured 
  in 
  some 
  

   particular 
  way, 
  why 
  do 
  we 
  find 
  them 
  mimicked 
  not 
  only 
  

   by 
  species 
  of 
  allied, 
  but 
  also 
  by 
  species 
  of 
  widely 
  separated 
  

   genera 
  ? 
  The 
  genus 
  Lema 
  is 
  to 
  be 
  distinguished 
  from 
  

   Diahrotica 
  by 
  decided 
  structural 
  differences. 
  In 
  Lema 
  

   the 
  antennae 
  are 
  inserted 
  far 
  apart, 
  and 
  the 
  prothorax 
  

   is 
  narrow 
  and 
  cylindrical 
  in 
  form. 
  In 
  Diahrotica 
  the 
  

   antennae 
  are 
  quite 
  close 
  together 
  at 
  their 
  points 
  of 
  

   insertion, 
  and 
  the 
  prothorax 
  is 
  somewhat 
  flattened, 
  and 
  

   has 
  sharp 
  lateral 
  edges. 
  The 
  two 
  genera 
  belong, 
  in 
  

   fact, 
  to 
  different 
  subfamilies. 
  Common 
  ancestry 
  cannot, 
  

   therefore, 
  be 
  regarded 
  as 
  a 
  possible 
  explanation 
  of 
  the 
  

   resemblance 
  between 
  species 
  of 
  the 
  two 
  genera. 
  Simi- 
  

   larity 
  in 
  their 
  surroundings 
  and 
  in 
  their 
  habits 
  of 
  life 
  

  

  