﻿PARASITES 
  OF 
  THE 
  HESSIAN 
  FLY. 
  , 
  217 
  

  

  united 
  and 
  forming 
  a 
  quite 
  solid 
  tube. 
  Some 
  species 
  are 
  wingless* 
  

   There 
  are 
  1,200 
  species 
  of 
  the 
  family 
  known 
  in 
  Europe, 
  and 
  there 
  are, 
  in 
  

   all 
  probability, 
  at 
  least 
  1,000 
  in 
  the 
  United 
  States. 
  Few 
  of 
  them 
  are 
  over 
  

   a 
  line 
  in 
  length. 
  

  

  Seiniotellus 
  destructor, 
  male. 
  (Plate 
  lY, 
  Fig. 
  ^, 
  much 
  enlarged.) 
  The 
  

   head 
  is 
  transversely 
  oblong, 
  or 
  rather 
  cubical, 
  being 
  rather 
  wider 
  than 
  

   long, 
  and 
  slightly 
  broader 
  than 
  the 
  thorax 
  when 
  seen 
  from 
  above, 
  being 
  

   full, 
  somewhat 
  rounded 
  in 
  front, 
  and 
  hollowed 
  out 
  behind 
  next 
  to 
  the 
  

   thorax. 
  The 
  eyes 
  are 
  dull 
  red, 
  reaching, 
  when 
  seen 
  above, 
  behind 
  the 
  

   middle 
  of 
  the 
  head. 
  The 
  antennse 
  are 
  elbowed, 
  and 
  when 
  bent 
  back 
  

   reach 
  to 
  about 
  the 
  middle 
  of 
  the 
  thorax 
  j 
  they 
  are 
  yellow 
  on 
  the 
  basal 
  

   half, 
  black 
  beyond. 
  In 
  the 
  male 
  they 
  are 
  lO-jointedj 
  the 
  scape 
  (joints 
  

   1-3) 
  is 
  pale, 
  and 
  free 
  from 
  hairs, 
  while 
  the 
  flagellum 
  (or 
  joints 
  4-10) 
  is 
  

   blackish 
  and 
  clothed 
  with 
  dense, 
  stiff 
  hairs 
  as 
  long 
  as 
  the 
  joint 
  is 
  thick. 
  

   The 
  fourth 
  joint 
  has 
  at 
  base 
  a 
  minute, 
  indistinct, 
  constricted 
  portion; 
  

   joints 
  5 
  to 
  9 
  are 
  of 
  equal 
  length 
  and 
  shorter 
  than 
  the 
  4th 
  joint 
  j 
  the 
  10th 
  

   (terminal) 
  joint 
  is 
  long 
  and 
  acute 
  at 
  the 
  tip, 
  and 
  nearly 
  twice 
  as 
  long 
  as 
  

   tlie 
  9th: 
  it 
  is 
  subdivided, 
  when 
  seen 
  under 
  a 
  J-inch 
  objective, 
  into 
  five 
  

   sub-joints, 
  the 
  5th 
  minute 
  and 
  acutely 
  conical. 
  

  

  The 
  thorax 
  is 
  about 
  twice 
  as 
  long 
  as 
  broad, 
  and 
  widest 
  at 
  the 
  inser- 
  

   tion 
  of 
  the 
  fore-wings 
  j 
  like 
  the 
  head, 
  the 
  crust 
  is 
  coarsely 
  punctured. 
  

   The 
  fore-wings 
  are 
  broad, 
  triangular, 
  well 
  rounded 
  externally 
  j 
  the 
  sub- 
  

   costal 
  vein 
  is 
  very 
  thick, 
  being 
  strongly 
  marked, 
  and 
  after 
  joining 
  the 
  

   costal 
  or 
  front 
  edge 
  of 
  the 
  wing 
  for 
  a 
  short 
  distance, 
  just 
  beyond 
  the 
  

   middle 
  of 
  the 
  wing, 
  is 
  bent 
  in 
  towards 
  the 
  middle 
  of 
  the 
  wing, 
  ending 
  

   in 
  a 
  knob-like 
  expansion 
  with 
  a 
  slight 
  point 
  extending 
  towards 
  the 
  cos- 
  

   tal 
  edge 
  of 
  the 
  wing. 
  Fitch 
  represents 
  a 
  slightly 
  marked 
  vein 
  extend- 
  

   ing 
  to 
  the 
  outer 
  edge 
  of 
  the 
  wing, 
  but 
  this 
  is 
  absent 
  in 
  our 
  specimens. 
  

   There 
  is 
  an 
  incomplete 
  median 
  and 
  submedian 
  vein, 
  only 
  perceptible 
  

   under 
  strong 
  magnifying 
  powers, 
  the 
  base 
  of 
  the 
  median 
  being 
  quite 
  

   disconnected 
  from 
  the 
  submedian. 
  In 
  most 
  of 
  my 
  specimens 
  there 
  was 
  

   no 
  vein 
  extending 
  from 
  the 
  subcostal 
  knob 
  to 
  the 
  end 
  of 
  the 
  wing. 
  

  

  The 
  legs 
  are 
  pale 
  straw-yellow, 
  the 
  fore 
  shank-joints 
  (tibiae) 
  and 
  toe- 
  

   joints 
  (tarsi) 
  brownish 
  ; 
  the 
  third 
  hip-joints 
  (femora) 
  are 
  dusky 
  on 
  the 
  ba- 
  

   sal 
  half, 
  while 
  the 
  hind 
  terminal 
  tarsal 
  joints 
  are 
  brown. 
  The 
  abdomen 
  is 
  

   small, 
  black, 
  while 
  the 
  head 
  and 
  thorax 
  are 
  bright 
  metallic 
  green, 
  some- 
  

   times 
  blue. 
  The 
  abdomen 
  is 
  also 
  smooth 
  and 
  polished, 
  much 
  flattened, 
  

   oval, 
  not 
  so 
  wide 
  as 
  the 
  thorax, 
  broad 
  at 
  the 
  end 
  and 
  suddenly 
  pointed 
  

   (mucronate) 
  at 
  the 
  tip. 
  It 
  has 
  a 
  large 
  yellowish 
  patch 
  on 
  the 
  upper 
  

   and 
  under 
  side 
  of 
  the 
  second 
  segment. 
  Length 
  of 
  the 
  body 
  2-2.6 
  milli- 
  

   meters 
  (0.08-0.11 
  inch). 
  

  

  The 
  female 
  differs 
  in 
  her 
  greater 
  size 
  and 
  rather 
  slenderer 
  body, 
  and 
  

   the 
  more 
  club-shaped 
  antennae, 
  the 
  terminal 
  joint 
  being 
  twice 
  as 
  long 
  as 
  

   thick. 
  Between 
  the 
  3d 
  and 
  4th 
  joints 
  are 
  two 
  distinct, 
  minute 
  subjoints, 
  

   the 
  2d 
  shorter 
  but 
  wider 
  than 
  the 
  1st; 
  joints 
  4-9 
  are 
  shorter 
  and 
  less 
  

  

  