﻿The 
  Grape-Seed 
  Fly. 
  137 
  

  

  interest 
  of 
  our 
  country, 
  and 
  which, 
  therefore, 
  should 
  be 
  

   promptly 
  met 
  and 
  circumvented 
  by 
  all 
  the 
  means 
  in 
  our 
  

   power. 
  

  

  The 
  bunch 
  of 
  grapes, 
  as 
  received, 
  contained 
  a 
  large 
  number 
  

   of 
  shriveled 
  berries, 
  upon 
  which, 
  as 
  also 
  upon 
  nearly 
  every 
  

   one 
  of 
  the 
  perfect 
  ones, 
  could 
  be 
  seen 
  with 
  the 
  naked 
  eye, 
  a 
  

   small 
  round 
  dot, 
  in 
  the 
  center 
  of 
  which 
  an 
  elevated 
  roughened 
  

   surface 
  was 
  visible 
  with 
  a 
  magnifier. 
  The 
  dot 
  marks 
  the 
  spot 
  

   where 
  a 
  very 
  minute 
  four-winged 
  fly 
  had 
  punctured 
  the 
  skin 
  

   and 
  deposited 
  its 
  egg. 
  The 
  egg 
  hatching, 
  the 
  larva 
  passes 
  

   through 
  the 
  pulp 
  into 
  one 
  of 
  the 
  seeds, 
  upon 
  the 
  kernel 
  of 
  

   which 
  it 
  feeds, 
  and 
  within 
  the 
  empty 
  case 
  undergoes 
  its 
  trans- 
  

   formation 
  to 
  its 
  pupal 
  state, 
  having 
  previously 
  provided 
  for 
  

   the 
  escape 
  of 
  the 
  perfect 
  fly 
  by 
  gnawing 
  an 
  aperture 
  of 
  suf- 
  

   ficient 
  size 
  in 
  the 
  seed. 
  

  

  For 
  the 
  detection 
  of 
  this 
  insect, 
  for 
  our 
  knowledge 
  of 
  its 
  

   habits 
  and 
  transformations, 
  and 
  for 
  its 
  description, 
  we 
  are 
  

   indebted 
  to 
  Mr. 
  W. 
  Saunders, 
  the 
  able 
  editor 
  of 
  the 
  Canadian 
  

   Entomologist, 
  who 
  first 
  observed 
  the 
  insect, 
  in 
  Canada, 
  in 
  the 
  

   fall 
  of 
  1868. 
  It 
  was 
  at 
  first 
  believed 
  by 
  him 
  to 
  be 
  the 
  larva 
  of 
  

   a 
  curculio, 
  but 
  subsequently 
  was 
  correctly 
  referred 
  by 
  Prof. 
  

   Riley 
  to 
  the 
  hymenopterous 
  genus 
  Isosoma. 
  In 
  the 
  Canadian 
  

   Entomologist 
  for 
  November, 
  1869, 
  it 
  is 
  described 
  by 
  Mr. 
  

   Saunders 
  as 
  Isosoma 
  vilis. 
  The 
  fly 
  is 
  quite 
  small, 
  being 
  

   but 
  about 
  one- 
  sixth 
  of 
  an 
  inch 
  in 
  spread 
  of 
  wings 
  ; 
  its 
  head, 
  

   thorax 
  and 
  abdomen 
  are 
  black, 
  the 
  wings 
  clear 
  and 
  iridescent, 
  

   and 
  the 
  legs 
  brown 
  and 
  black. 
  The 
  species 
  is 
  interesting 
  from 
  

   its 
  belonging 
  to 
  the 
  same 
  genus 
  with 
  the 
  destructive 
  joint- 
  

   worm 
  fly, 
  the 
  Isosoma 
  Tiordei 
  (Harris), 
  which 
  has 
  proved 
  so 
  

   very 
  destructive 
  to 
  the 
  wheat, 
  rye 
  and 
  barley 
  crops 
  ; 
  and, 
  

   perhaps, 
  even 
  more 
  interesting 
  from 
  a 
  remarkable 
  difference 
  

   in 
  the 
  sexes, 
  pointed 
  out 
  by 
  the 
  late 
  Mr. 
  Walker 
  of 
  the 
  British 
  

   Museum, 
  "one 
  of 
  them 
  representing 
  the 
  carnivorous 
  Eury- 
  

   toma, 
  and 
  the 
  other 
  the 
  herbivorous 
  Isosoma, 
  and 
  thus 
  one 
  

   species 
  figuratively 
  combines 
  the 
  diminishers 
  of 
  vegetation 
  

   and 
  the 
  controllers 
  of 
  such 
  diminution." 
  

  

  In 
  an 
  account 
  of 
  this 
  insect 
  Mr. 
  Saunders 
  says 
  : 
  ' 
  ' 
  On 
  the 
  

   20th 
  of 
  August, 
  1868, 
  we 
  observed 
  that 
  many 
  of 
  the 
  berries 
  in 
  

   the 
  bunches 
  of 
  a 
  Clinton 
  vine, 
  under 
  our 
  care, 
  were 
  shrivel- 
  

   ing 
  up. 
  On 
  opening 
  the 
  grapes, 
  we 
  noticed 
  that 
  most 
  of 
  the 
  

   smaller 
  berries 
  — 
  that 
  is, 
  those 
  which 
  had 
  shriveled 
  earliest 
  — 
  

   contained 
  only 
  one 
  seed, 
  and 
  that 
  of 
  an 
  unusually 
  large 
  size 
  ; 
  

  

  