﻿THE 
  LARVAL 
  AND 
  PUPAL 
  STAGES 
  OF 
  THE 
  BIBIONIDAE 
  — 
  PART 
  II. 
  

  

  193 
  

  

  very 
  well 
  developed 
  posterior 
  caecum 
  opening 
  ventrally 
  from 
  near 
  the 
  posterior 
  end 
  

   of 
  the 
  mesenteron, 
  and 
  directed 
  anteriorly. 
  The 
  anterior 
  caeca 
  have 
  a 
  lobe 
  at 
  their 
  

   anterior 
  end, 
  these 
  lobes 
  having 
  almost 
  the 
  appearance 
  of 
  three 
  small 
  additional 
  

   caeca. 
  The 
  Malpighian 
  tubes 
  enter 
  the 
  alimentary 
  canal 
  by 
  a 
  very 
  short 
  common 
  

   duct, 
  as 
  is 
  the 
  case 
  in 
  Bibio 
  larvae. 
  

  

  Pupa. 
  

  

  Elongate, 
  cylindrical, 
  tapering 
  gently 
  to 
  posterior 
  end, 
  abruptly 
  at 
  anterior 
  end. 
  

   Completely 
  free 
  from 
  larval 
  skin. 
  Colour 
  at 
  first 
  white, 
  head 
  and 
  thorax 
  of 
  imago 
  

   showing 
  dark 
  through 
  cuticle 
  later. 
  Length, 
  7-5 
  mm. 
  

  

  Male 
  (fig. 
  9). 
  Head 
  with 
  3 
  conspicuous 
  pointed 
  processes 
  at 
  anterior 
  end, 
  

   1 
  median 
  and 
  2 
  slightly 
  ventral 
  to 
  it 
  arising 
  from 
  the 
  eyes, 
  which 
  are 
  large 
  and 
  

   conspicuous. 
  

  

  Fig. 
  9. 
  Pupa 
  of 
  Diloph 
  us 
  febrilis, 
  £, 
  ventral 
  view, 
  X 
  18. 
  

  

  Female 
  (fig. 
  10). 
  Head 
  with 
  a 
  single 
  stout 
  median 
  process 
  at 
  anterior 
  end. 
  Eyes 
  

   much 
  smaller 
  than 
  in 
  the 
  male. 
  

  

  Fig 
  

  

  10. 
  Pupa 
  of 
  Dilophus 
  jebrilis, 
  <£, 
  dorsal 
  view, 
  x 
  18. 
  

  

  Male 
  and 
  female. 
  A 
  slight 
  dorsal 
  ridge 
  extends 
  from 
  anterior 
  median 
  process 
  to 
  

   posterior 
  margin 
  of 
  thorax, 
  along 
  which 
  dehiscence 
  for 
  the 
  emergence 
  of 
  the 
  imago 
  

   occurs. 
  Antennae 
  extremely 
  short, 
  arising 
  between 
  bases 
  of 
  eyes, 
  and 
  extending 
  

   laterally 
  over 
  eyes, 
  with 
  a 
  small 
  conical 
  process 
  on 
  base. 
  Labium 
  elongate, 
  semi- 
  

   circular 
  ; 
  labial 
  palpi 
  elongate, 
  extending 
  laterally. 
  Dorsally 
  most 
  of 
  head 
  covered 
  

   by 
  prothorax, 
  only 
  eyes 
  of 
  male 
  visible. 
  

  

  Thorax 
  strongly 
  arched 
  dorsally. 
  The 
  thoracic 
  spiracles 
  slightly 
  projecting 
  

   laterally. 
  Tibiae 
  and 
  tarsi 
  of 
  forelegs 
  extending 
  from 
  side 
  of 
  eyes 
  level 
  with 
  antennae 
  

   to 
  anterior 
  margin 
  of 
  second 
  abdominal 
  segment, 
  with 
  tarsi 
  in 
  apposition 
  along 
  

   median 
  line. 
  Second 
  and 
  third 
  pairs 
  of 
  legs 
  parallel 
  to 
  first 
  ; 
  all 
  except 
  tibiae 
  and 
  

   first 
  and 
  last 
  tarsal 
  segments 
  of 
  second, 
  and 
  last 
  tarsal 
  segment 
  of 
  third, 
  covered 
  

   by 
  wings. 
  

  

  Abdomen 
  nine-segmented, 
  tapering 
  to 
  posterior 
  end, 
  the 
  ninth 
  segment 
  being 
  

   conical. 
  Cuticle 
  with 
  many 
  wrinkles, 
  mainly 
  transverse. 
  Abdominal 
  segments, 
  

   dorsally 
  and 
  ventrally, 
  bearing 
  numerous 
  spines 
  similar 
  to 
  those 
  of 
  the 
  larva, 
  usually 
  

   occurring 
  singly 
  on 
  slight 
  swellings 
  of 
  the 
  cuticle. 
  Terminal 
  segment 
  bearing 
  a 
  pair 
  

   of 
  stout 
  pointed 
  processes 
  at 
  the 
  posterior 
  end, 
  directed 
  posteriorly 
  and 
  outwards, 
  

   and 
  a 
  pair 
  of 
  rounded 
  papillae 
  anterior 
  to 
  them, 
  on 
  which 
  the 
  spiracles 
  of 
  this 
  segment 
  

   are 
  situated. 
  Each 
  segment 
  of 
  abdomen, 
  except 
  eighth, 
  bearing 
  a 
  pair 
  of 
  slightly 
  

   projecting 
  spiracles 
  situated 
  laterally 
  towards 
  the 
  anterior 
  margin 
  of 
  the 
  segment. 
  

  

  