﻿PACKAED.l 
  PARASITES 
  OF 
  NORTHERN 
  ARMY-WORM. 
  705 
  

  

  character 
  is 
  the 
  long 
  compressed 
  abdomen, 
  which, 
  much 
  arched 
  or 
  sickle- 
  

   shaped, 
  is 
  attached 
  to 
  the 
  body 
  by 
  a 
  slender 
  peduncle. 
  The 
  end 
  of 
  the 
  

   abdomen 
  is 
  cut 
  off 
  obliquely 
  inwards 
  below. 
  The 
  ovipositor 
  is 
  scarcely 
  

   to 
  be 
  seen, 
  which 
  in 
  most 
  ichneumons 
  is 
  very 
  long 
  ; 
  and 
  here 
  we 
  see 
  

   the 
  adaptation 
  of 
  this 
  organ 
  to 
  the 
  habits 
  of 
  the 
  species. 
  Instead 
  of 
  

   piercing 
  the 
  body 
  of 
  the 
  victim 
  and 
  depositing 
  the 
  egg 
  at 
  the 
  bottom 
  of 
  

   the 
  wound, 
  the 
  Ophion 
  merely 
  lays 
  its 
  egg 
  on 
  the 
  skin 
  of 
  the 
  caterpillar. 
  

   The 
  egg 
  is 
  bean-shaped 
  and 
  attached 
  by 
  a 
  pedicle 
  to 
  the 
  skin. 
  When 
  

   the 
  footless 
  grub 
  is 
  hatched 
  it 
  does 
  not 
  entirely 
  leave 
  the 
  egg-case, 
  but 
  

   the 
  last 
  joints 
  of 
  its 
  body 
  remain 
  attached 
  to 
  the 
  shell, 
  while 
  it 
  reaches 
  

   out 
  over 
  and 
  with 
  its 
  sharp 
  jaw-pieces 
  gnaws 
  into 
  the 
  side 
  of 
  the 
  cater- 
  

   pillar. 
  Some 
  Ophioiis 
  are 
  parasitic 
  in 
  their 
  ichneumons, 
  just 
  as 
  are 
  

   the 
  species 
  of 
  Chalcis 
  mentioned 
  below. 
  

  

  This 
  species, 
  common 
  in 
  Maine, 
  is 
  of 
  a 
  pale-reddish 
  horn 
  color. 
  The 
  head 
  is 
  yellow, 
  

   pale 
  testaceous 
  at 
  the 
  base 
  of 
  the 
  antenufe. 
  The 
  large 
  prominent 
  eves 
  black. 
  Three 
  

   smaller 
  black 
  simple 
  eyes 
  are 
  arranged 
  in 
  a 
  triangle 
  above, 
  between 
  the 
  compound 
  

   eyes. 
  The 
  rest 
  of 
  the 
  body, 
  especially 
  the 
  hind 
  part 
  of 
  the 
  thorax, 
  and 
  the 
  joints 
  and 
  

   under 
  side 
  of 
  the 
  abdomen 
  and 
  legs 
  beneath 
  are 
  covered 
  by 
  a 
  bloom 
  of 
  minute 
  lighter- 
  

   colored 
  hairs 
  which 
  have 
  their 
  origin 
  in 
  microscopic 
  punctures. 
  On 
  the 
  middle 
  of 
  the 
  

   thorax 
  above, 
  a 
  little 
  darker 
  ; 
  aud 
  behind, 
  a 
  yellowish 
  tint. 
  Next 
  the 
  insertion 
  of 
  the 
  

   abdomea 
  the 
  thorax 
  is 
  thickly 
  and 
  plainly 
  punctate. 
  Same 
  color 
  beneath, 
  except 
  the 
  

   first 
  three 
  joints 
  of 
  the 
  abdomen, 
  which 
  are 
  touched 
  with 
  yellow, 
  and 
  the 
  lower 
  side 
  is 
  

   generally 
  darker. 
  

  

  The 
  veins 
  of 
  the 
  wings 
  are 
  dark; 
  the 
  thickened 
  cell 
  on 
  the 
  front 
  margin 
  of 
  the 
  fore 
  

   wiugs 
  and 
  the 
  adjacent 
  veins 
  as 
  well 
  as 
  the 
  horny 
  triangular 
  pieces 
  in 
  the 
  cell 
  below, 
  

   the 
  outer 
  of 
  which 
  is 
  much 
  the 
  smallest, 
  are 
  pale 
  horn 
  color. 
  

  

  Body 
  nearly 
  an 
  inch 
  long. 
  Expanse 
  of 
  wings, 
  12^ 
  tenths. 
  

  

  Mr. 
  Walsh, 
  of 
  Illinois, 
  has 
  discovered 
  three 
  other 
  ichneumons, 
  descrip- 
  

   tions 
  of 
  which 
  we 
  take 
  from 
  his 
  pamphlet 
  : 
  

  

  Mesocliorus 
  vilreus 
  Walsh. 
  — 
  Male, 
  general 
  color 
  light 
  rufous. 
  Eyes 
  and 
  ocelli 
  black, 
  

   antenna) 
  fuscous 
  except 
  toward 
  the 
  base. 
  Upper 
  surface 
  of 
  thorax 
  in 
  the 
  larger 
  speci- 
  

   men 
  fuscous; 
  intermediate 
  and 
  posterior 
  tibite 
  with 
  spurs 
  equal 
  to 
  one-fourth 
  their 
  

   length 
  ; 
  posterior 
  kuees 
  slightly 
  dusky 
  ; 
  tips 
  of 
  posterior 
  tibiae 
  distinctly 
  dusky. 
  

   Wiugs 
  hyaline, 
  nervures 
  and 
  stigma 
  dusky. 
  Abdomen 
  viewed 
  in 
  profile, 
  curves 
  con- 
  

   siderably, 
  especially 
  at 
  base, 
  and 
  is 
  quite 
  narrow, 
  except 
  toward 
  the 
  tip, 
  where 
  it 
  

   expands 
  suddenly. 
  The 
  abdomen 
  of 
  the 
  male 
  is 
  appendiculated. 
  It 
  is 
  of 
  a 
  translucent 
  

   yellowish-white 
  in 
  its 
  central 
  one-third; 
  the 
  remaining 
  two-thirds 
  x^iceous 
  black, 
  with 
  

   a 
  distinct 
  yellowish 
  narrow 
  annulus 
  at 
  the 
  base 
  of 
  the 
  third 
  joint. 
  Appeudiculum 
  of 
  

   abdomen 
  composed 
  of 
  two 
  extremely 
  fine 
  seta?, 
  thickened 
  at 
  their 
  base, 
  whose 
  length 
  

   slightly 
  exceeds 
  the 
  extreme 
  width 
  of 
  the 
  abdomen. 
  

  

  The 
  female 
  differs 
  in 
  the 
  head, 
  being 
  from 
  the 
  mouth 
  upward 
  piceous. 
  The 
  thorax 
  

   and 
  pectus 
  are 
  piceous 
  black. 
  Ovipositor, 
  which 
  is 
  dusky, 
  slightlj' 
  exceeds 
  in 
  length 
  

   the 
  width 
  of 
  the 
  abdomen. 
  Body, 
  .08-.03 
  inch 
  long. 
  

  

  Pezomaclms 
  minimus 
  Walsh. 
  — 
  This 
  genus 
  is 
  wingless, 
  like 
  the 
  neuters 
  

   of 
  ants, 
  except 
  that 
  their 
  antennae 
  are 
  not 
  elbowed 
  like 
  those 
  of 
  ants. 
  

  

  Male, 
  piceous. 
  Eyes 
  black, 
  antenna? 
  black, 
  except 
  toward 
  the 
  base, 
  where 
  they 
  are 
  

   light 
  rufous. 
  Legs 
  rufous, 
  hinds 
  legs 
  a 
  little 
  dusky. 
  Abdomen 
  narrowed 
  ; 
  second 
  and 
  

   sometimes 
  third 
  joint 
  annulate 
  with 
  rufous 
  at 
  tip. 
  The 
  female 
  differs 
  in 
  the 
  thorax, 
  

   being 
  almost 
  invariably 
  rufous, 
  and 
  in 
  the 
  first 
  three 
  abdominal 
  joints 
  being 
  generally 
  

   entirely 
  rufous, 
  with 
  a 
  piceous 
  auuulns 
  at 
  the. 
  base 
  of 
  the 
  third, 
  though 
  sometimes 
  

   absent. 
  The 
  abdomen 
  is 
  also 
  fuller 
  and 
  wider. 
  Ovipositor 
  dusky, 
  equal 
  in 
  length 
  to 
  

   the 
  width 
  of 
  the 
  abdomen. 
  Body 
  .07 
  to 
  .1 
  inch 
  long. 
  

  

  The 
  cocoons 
  symmetrically 
  arranged 
  side 
  by 
  side, 
  and 
  enveloped 
  in 
  

   floss, 
  are 
  found 
  in 
  the 
  dead 
  skins 
  of 
  the 
  army-worm. 
  A 
  minute 
  ichneu- 
  

   mon, 
  Chalcis 
  albifrons 
  Walsh, 
  was 
  bred 
  from 
  the 
  cocoons 
  of 
  the 
  Pcco- 
  

   machus. 
  

  

  Microgaster 
  milifaris 
  Walsh, 
  is 
  another 
  army-worm 
  parasite. 
  Head 
  black; 
  palpi 
  

   "whitish 
  ; 
  anteunte, 
  fuscous 
  above, 
  light 
  brown 
  beneath 
  toward 
  the 
  base. 
  Thorax 
  

   black, 
  polished 
  with 
  very 
  minute 
  punctures. 
  Nervures 
  and 
  stigma 
  of 
  the 
  wing 
  fus- 
  

   cous. 
  Legs 
  light 
  rufous, 
  posterior 
  pair 
  Avith 
  knees 
  and 
  tips 
  of 
  tibifo 
  fuscous. 
  Abdo- 
  

   men 
  black, 
  glabrous, 
  highly 
  polished. 
  Ovipositor 
  not 
  exserted. 
  Length 
  of 
  body, 
  .07 
  

   inch. 
  

  

  45 
  G 
  S 
  

  

  