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  XIII. 
  Mimetic 
  resemblances 
  betweoi 
  species 
  of 
  the 
  Coleo- 
  

   pterous 
  genera 
  Lema 
  and 
  Diabrotica. 
  By 
  Charles 
  

   J. 
  Gahan, 
  M.A., 
  F.E.S., 
  Assistant 
  in 
  the 
  Zoological 
  

   Department, 
  British 
  Museum. 
  

  

  [Eead 
  March 
  4th, 
  1891.1 
  

  

  Plate 
  XVII. 
  

  

  When, 
  a 
  short 
  time 
  ago, 
  I 
  began 
  to 
  work 
  at 
  the 
  phyto- 
  

   phagous 
  genus 
  Diahrotica, 
  I 
  was 
  somewhat 
  puzzled 
  to 
  

   account 
  for 
  the 
  strangely 
  familiar 
  appearances 
  of 
  some 
  

   of 
  the 
  species 
  ; 
  for 
  I 
  had 
  never 
  any 
  reason, 
  until 
  then, 
  

   to 
  examine 
  them 
  very 
  closely. 
  Upon 
  a 
  little 
  reflection, 
  

   however, 
  I 
  suspected 
  that, 
  by 
  looking 
  into 
  the 
  cabinet 
  

   drawers 
  containing 
  the 
  species 
  of 
  Lema, 
  which 
  I 
  had 
  

   not 
  long 
  before 
  arranged, 
  I 
  should 
  be 
  able 
  to 
  find 
  the 
  

   needful 
  explanation. 
  This 
  suspicion 
  proved 
  correct. 
  

   Certain 
  species 
  of 
  Lema 
  were 
  seen 
  to 
  have 
  the 
  closest 
  

   resemblance 
  in 
  colour 
  and 
  marking 
  to 
  those 
  species 
  of 
  

   Diabrotica 
  which 
  had 
  so 
  perplexed 
  me. 
  

  

  If 
  only 
  one 
  or 
  two 
  out 
  of 
  the 
  five 
  hundred 
  species 
  of 
  

   Lema 
  resembled 
  one 
  of 
  the 
  four 
  hundred 
  or 
  more 
  species 
  

   of 
  Diabrotica, 
  the 
  fact 
  need 
  not 
  be 
  considered 
  very 
  

   extraordinary 
  ; 
  but 
  it 
  certainly 
  does 
  seem 
  deserving 
  of 
  

   notice 
  that 
  as 
  many 
  as 
  fifteen 
  or 
  sixteen 
  species 
  of 
  the 
  

   one 
  genus 
  should 
  present 
  the 
  most 
  striking 
  analogical 
  

   resemblances 
  to 
  corresponding 
  species 
  of 
  the 
  other. 
  The 
  

   resemblance, 
  it 
  need 
  scarcely 
  be 
  said, 
  was 
  found 
  to 
  be 
  most 
  

   pronounced 
  between 
  specimens 
  from 
  the 
  same 
  localities. 
  

  

  It 
  would 
  be 
  fruitless 
  to 
  attempt 
  to 
  convey 
  by 
  descrip- 
  

   tion 
  a 
  clear 
  idea 
  of 
  the 
  similarity 
  in 
  colour 
  and 
  style 
  of 
  

   marking 
  ; 
  so 
  that 
  I 
  do 
  not 
  intend 
  to 
  give 
  here 
  more 
  than 
  

   a 
  brief 
  indication 
  of 
  the 
  points 
  of 
  resemblance 
  between 
  a 
  

   few 
  of 
  the 
  species. 
  

  

  In 
  Diabrotica 
  10-guttata, 
  Oliv. 
  (see 
  Baly) 
  — 
  a 
  very 
  

   variable 
  species, 
  occurring 
  abundantly 
  in 
  the 
  Amazonian 
  

   regions 
  — 
  the 
  head 
  is 
  black, 
  the 
  eighth 
  and 
  ninth 
  joints 
  

   of 
  the 
  antennae 
  are 
  whitish, 
  the 
  remaining 
  joints 
  brownish 
  

  

  TRANS, 
  ENT. 
  SOC. 
  LOND. 
  1891. 
  PART 
  II. 
  (jUNE.) 
  

  

  