﻿[14] 
  REPOET 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  the 
  Dumber 
  of 
  joints 
  is 
  2+14 
  to 
  2-|-16, 
  usually 
  2+15. 
  The 
  female, 
  

   therefore, 
  has 
  on 
  an 
  average 
  one 
  flagellar 
  joint 
  less 
  than 
  the 
  male.* 
  

  

  Of 
  the 
  very 
  short-stemmed, 
  cylindric-oval 
  flagellar 
  joints 
  the 
  lower 
  

   ones 
  are 
  a 
  little 
  longer 
  than 
  those 
  toward 
  the 
  terminus: 
  the 
  last 
  joint 
  

   is 
  also 
  regularly 
  longer 
  than 
  the 
  penultimate, 
  sometimes 
  but 
  little, 
  but 
  

   the 
  plus 
  is 
  often 
  a 
  full 
  one-third 
  of 
  the 
  length, 
  f 
  

  

  Of 
  the 
  verticillate 
  hairs 
  those 
  jflaced 
  toward 
  the 
  base 
  attain 
  the 
  

   length 
  of 
  the 
  flagellar 
  knots; 
  the 
  pilosity 
  of 
  the 
  female 
  is 
  altogether 
  

   much 
  shorter 
  than 
  in 
  the 
  male. 
  The 
  wings 
  reach 
  much 
  less 
  beyond 
  the 
  

   abdomen 
  than 
  in 
  the 
  male. 
  The 
  abdomen 
  is 
  cylindrical, 
  gradually 
  taper- 
  

   ing 
  from 
  the 
  sixth 
  segment. 
  The 
  rose-red-colored 
  ovipositor 
  consists 
  of 
  

   a 
  cylindrical 
  basal 
  joint 
  and 
  a 
  one-third 
  longer, 
  posteriorly 
  rounded, 
  

   short 
  haired 
  terminal 
  joint. 
  The 
  genital 
  orifice 
  is 
  not 
  at 
  the 
  end 
  of 
  the 
  

   ovipositor, 
  but 
  below 
  at 
  the 
  hind 
  margin 
  of 
  the 
  basal 
  joint. 
  The 
  very 
  

   convenient 
  position 
  of 
  the 
  terminal 
  joint 
  for 
  the 
  fertilization 
  of 
  eggs 
  

   while 
  passing 
  out 
  of 
  the 
  parent 
  leads 
  us 
  to 
  suggest 
  the 
  presence 
  in 
  it 
  of 
  

   a 
  ^'seminal 
  receptacle." 
  The 
  great 
  flexibility 
  of 
  the 
  last 
  segment 
  allows 
  

   the 
  female 
  fly 
  to 
  direct 
  the 
  ovipositor 
  downward, 
  which 
  can 
  best 
  be 
  ob- 
  

   served 
  in 
  the 
  moment 
  of 
  oviposition. 
  No 
  trace 
  can 
  be 
  found 
  of 
  certain 
  

   small 
  lamellge 
  usually 
  occuring 
  in 
  gall-gnats 
  at 
  the 
  abdominal 
  end. 
  

  

  Loew, 
  in 
  his 
  monograph, 
  states 
  as 
  an 
  artificial 
  character 
  of 
  the 
  gall- 
  

   gnats 
  : 
  

  

  Body 
  long, 
  cylindrical. 
  Legs 
  slender, 
  tibise 
  always 
  unarmecT, 
  claws 
  weak, 
  only 
  one 
  

   claw-cusliion. 
  Wings 
  large 
  and 
  broad, 
  without 
  appendage, 
  with 
  three 
  to 
  live 
  longi- 
  

   tudinal 
  and 
  scarcely 
  one 
  transverse 
  vein, 
  which 
  is 
  placed 
  between 
  the 
  first 
  and 
  second 
  

   longitudinal 
  veins; 
  wing-margin 
  ciliate, 
  with 
  but 
  seven 
  sections; 
  surface 
  of 
  wing 
  all 
  

   over 
  with 
  long 
  or 
  shorter 
  intermingled 
  with 
  longer 
  pilosity. 
  

  

  By 
  a 
  glance 
  at 
  the 
  above 
  description 
  the 
  family 
  character 
  will 
  be 
  re- 
  

   cognized. 
  Our 
  insect 
  is, 
  therefore, 
  really 
  a 
  gall-gnat. 
  As 
  the 
  first 
  tarsal 
  

   joint 
  is 
  the 
  shortest 
  and 
  no 
  ocelli 
  occur, 
  the 
  insect 
  belongs 
  to 
  that 
  group 
  

   of 
  gall-gnats 
  which 
  comprises 
  the 
  two 
  genera 
  Cecidomyia 
  Meig. 
  and 
  Lasi- 
  

   optera 
  Meig. 
  (excluding 
  the 
  species 
  with 
  non-abbreviated 
  first 
  tarsal 
  

   joint). 
  Only 
  the 
  first 
  longitudinal 
  vein 
  of 
  the 
  wings 
  approaches 
  more 
  

   the 
  anterior 
  margin 
  ; 
  therefore 
  the 
  i 
  nsect 
  belongs 
  to 
  the 
  genus 
  Cecido^ 
  

   myia. 
  Winnertz 
  subdivides 
  this 
  genus 
  into 
  eight 
  subgenera. 
  The 
  run- 
  

   ning 
  out 
  of 
  the 
  second 
  longitudinal 
  vein 
  before 
  reaching 
  the 
  end 
  of 
  the 
  

   wing 
  and 
  the 
  nearly 
  equal 
  number 
  of 
  antennal 
  joints 
  in 
  both 
  sexes 
  

   allots 
  our 
  insect 
  strictly 
  to 
  the 
  subgenus 
  Cecidomyia, 
  

  

  § 
  3. 
  — 
  Winter 
  generation. 
  

  

  The 
  period 
  from 
  the 
  ^gg 
  up 
  to 
  the 
  imago 
  occurs 
  in 
  the 
  life 
  history 
  of 
  

   this 
  insect 
  twice 
  annually, 
  i. 
  e., 
  the 
  fly 
  appears 
  in 
  two 
  generations 
  every 
  

   year. 
  That 
  we 
  besides 
  this 
  have 
  to 
  distinguish 
  also 
  another 
  hitherto 
  

   overlooked 
  case 
  I 
  shall 
  demonstrate 
  at 
  the 
  end 
  of 
  this 
  paragraph. 
  At 
  

   present 
  we 
  will 
  speak 
  of 
  that 
  generation 
  wlaich 
  is 
  produced 
  by 
  the 
  flies 
  

   hatching 
  in 
  the 
  fall. 
  We 
  will 
  call 
  it, 
  since 
  it 
  belongs 
  to 
  the 
  cold 
  season, 
  

   the 
  winter 
  generation. 
  

  

  * 
  An 
  exatnination 
  of 
  all 
  the 
  raised 
  specimens 
  teaches 
  lis 
  that 
  the 
  normal 
  number 
  for 
  the 
  antennal 
  

   joints 
  (cT 
  2-4-16, 
  $ 
  2 
  -f 
  15) 
  on 
  the 
  average 
  suffers 
  in 
  seven 
  cases 
  two 
  exceptions, 
  i. 
  e., 
  having 
  one 
  more 
  

   joint 
  or 
  one 
  less. 
  f 
  

  

  tThe 
  small 
  stylet 
  connecting 
  both 
  terminal 
  joints 
  Tve 
  not 
  uncommonly 
  find 
  to 
  be 
  reduced 
  to 
  a 
  mini- 
  

   mum, 
  so 
  that 
  it 
  is 
  rather 
  difficult 
  to 
  tell 
  -whether 
  there 
  are 
  two 
  or 
  but 
  one 
  joint. 
  To 
  escape 
  any 
  doubt 
  

   the 
  following 
  remark 
  will 
  be 
  of 
  advantage 
  : 
  AVhere 
  at 
  least 
  a 
  transverse 
  groove 
  is 
  indicated 
  I 
  decided 
  

   for 
  two 
  joints 
  ; 
  where 
  this 
  could 
  not 
  be 
  found 
  I 
  accepted 
  but 
  one 
  joint, 
  even 
  if 
  the 
  proportional 
  length 
  

  

  Serhaps 
  recalled 
  the 
  possibility 
  of 
  two 
  connate 
  joints. 
  It 
  often 
  occurs 
  that 
  some 
  joints 
  may 
  be 
  sub- 
  

   ivided 
  by 
  a 
  constriction 
  into' 
  two 
  smaller 
  joints. 
  This 
  modification, 
  a 
  consequence 
  of 
  mechanical 
  

   pressure 
  or 
  of 
  having 
  been 
  dried 
  up 
  alter 
  death, 
  will 
  never 
  leave 
  the 
  observer 
  in 
  doubt 
  as 
  to 
  the 
  real 
  

   number 
  of 
  antennal 
  joints, 
  when 
  he 
  considers 
  their 
  normal 
  proportion 
  of 
  length 
  and 
  the 
  manner 
  in 
  

   •which 
  they 
  are 
  linked 
  together. 
  

  

  