﻿WAGNER 
  ON 
  THE 
  HESSIAN 
  FLY. 
  

  

  [21] 
  

  

  curate 
  results 
  as 
  to 
  the 
  determination 
  of 
  the 
  swarming 
  time. 
  With 
  the 
  

   consciousness 
  of 
  having 
  previously 
  obtained 
  certainty 
  as 
  to 
  the 
  actual 
  

   occurrence 
  of 
  the 
  fly 
  on 
  winter 
  rye 
  I 
  became 
  contented 
  to 
  make 
  use 
  of 
  

   the 
  occurrence 
  on 
  barley 
  aftergrowth 
  On 
  fields 
  with 
  young 
  clover 
  the 
  

   straw 
  of 
  this 
  aftergrowth 
  preserved 
  for 
  a 
  rather 
  long 
  period 
  the 
  pseudo- 
  

   chrysalids 
  I 
  gathered 
  dbout 
  the 
  middle 
  of 
  March. 
  The 
  result 
  is 
  tabled 
  

   as 
  below 
  : 
  

  

  Kind 
  of 
  crops. 
  

  

  fcJC 
  

  

  a 
  

   1 
  

  

  p 
  

  

  Sex. 
  

  

  Number 
  of 
  an- 
  

   tenjial 
  joints. 
  

  

  Eh 
  

  

  gi 
  

  

  H 
  

  

  1 
  

  

  a 
  

  

  m 
  

  

  

  April 
  21 
  

  

  21 
  

  

  22 
  

  

  22 
  

  

  22 
  

  

  23 
  

  

  24 
  

  

  25 
  

  

  25 
  

  

  26 
  

  

  28 
  

  

  30 
  

  

  May 
  2 
  

  

  5 
  

  

  5 
  

  

  5 
  

  

  7 
  

  

  9 
  

  

  10 
  

  

  10 
  

  

  10 
  

  

  10 
  

  

  10 
  

  

  12 
  

  

  14 
  

  

  18 
  

  

  18 
  

  

  "d 
  

  

  "d 
  

   cT 
  

  

  

  

  

  

  17 
  

  

  

  

  

  

  

  15 
  

   15 
  

  

  

  

  

  

  

  

  

  

  

  

  

  ^ 
  

  

  14- 
  

   14 
  

  

  

  

  

  

  

  15 
  

  

  

  

  

  

  

  

  

  

  

  

  15 
  

   15 
  

  

  

  

  

  

  

  16 
  

  

  

  

  

  

  ? 
  

  

  .... 
  

  

  15 
  

   15 
  

   15 
  

   15 
  

  

  

  

  

  

  

  

  

  

  

  

  9 
  

   ? 
  

  

  14 
  

  

  

  

  

  

  

  

  

  

  

  

  

  16 
  

   16 
  

  

  

  

  

  

  

  

  15 
  

  

  

  

  

  

  ? 
  

  

  

  

  

  

  

  

  15 
  

   15 
  

   15 
  

  

  

  

  

  

  ? 
  

   ? 
  

  

  .... 
  

  

  

  

  

  

  

  

  

  

  

  

  16 
  

  

  

  

  

  

  'ii 
  

  

  15 
  

   15 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  15 
  

   15 
  

  

  16 
  

  

  

  

  

  ' 
  

  

  

  

  

  

  ? 
  

  

  

  

  

  

  

  

  

  

  

  Alto""etlier 
  

  

  9 
  

  

  18 
  

  

  4 
  

  

  17 
  

  

  5 
  

  

  1 
  

  

  1:2 
  

  

  27 
  

  

  

  

  

  An 
  explanation 
  of 
  the 
  table 
  is 
  scarcely 
  necessary. 
  We 
  again 
  notice 
  

   a 
  preponderance 
  of 
  females 
  over 
  the 
  males; 
  12 
  females 
  have 
  2+15, 
  four 
  

   females 
  2+14, 
  and 
  only 
  two 
  2+16 
  jointed 
  antennae. 
  Of 
  the 
  nine 
  males 
  

   five 
  specimeus 
  have 
  2 
  + 
  15 
  joints, 
  only 
  three 
  2+16, 
  one 
  2+15-jointed 
  

   antennae. 
  In 
  regard 
  to 
  the 
  former 
  table, 
  comprising 
  more 
  individuals, 
  

   the 
  formula 
  2+16 
  must 
  be 
  held 
  as 
  the 
  normal 
  number 
  of 
  the 
  male 
  an- 
  

   tennal 
  joints. 
  

  

  Before 
  answering 
  the 
  question 
  as 
  to 
  the 
  duration 
  of 
  the 
  spring 
  swarm- 
  

   ing 
  time, 
  I 
  draw 
  the 
  attention 
  of 
  the 
  reader 
  to 
  a 
  discovery 
  mentioned 
  at 
  

   the 
  beginning 
  of 
  this 
  paragraph. 
  I 
  visited 
  on 
  March 
  23 
  a 
  field 
  with 
  

   young 
  clover, 
  which 
  had 
  been 
  sown 
  between 
  winter 
  wheat 
  of 
  last 
  year, 
  

   of 
  which, 
  therefore,^only 
  the 
  stubble 
  was 
  left. 
  On 
  the 
  latter 
  I 
  discovered, 
  

   with 
  no 
  little 
  surprise, 
  pseudo-pupae 
  of 
  our 
  insect, 
  which 
  on 
  closer 
  in- 
  

   spection 
  proved 
  to 
  be 
  alive. 
  Investigations 
  during 
  several 
  successive 
  

   days 
  always 
  only 
  revealed 
  such 
  covered 
  maggots. 
  On 
  April 
  2 
  I 
  found 
  

   also 
  some 
  pupae 
  proper 
  on 
  the 
  same 
  field 
  ; 
  two 
  days 
  afterwards 
  pupae 
  

   only. 
  That 
  the 
  insects 
  so 
  rapidly 
  transformed 
  into 
  pupae 
  I 
  princii3ally 
  

   ascribed 
  to 
  tlie 
  sudden 
  warm 
  weather. 
  Of 
  the 
  xiupae 
  preserved 
  in 
  the 
  

   manner 
  previously 
  stated, 
  the 
  first 
  fly 
  hatched 
  on 
  April 
  13, 
  so 
  that 
  the 
  

   duration 
  of 
  spring 
  pupation 
  would 
  be 
  twelve 
  to 
  fourteen 
  days. 
  Up 
  to 
  

   May 
  12 
  the 
  i)ux)ae 
  yielded 
  altogether 
  ten 
  flies, 
  %. 
  e., 
  three 
  males 
  and 
  seven 
  

   females. 
  

  

  