﻿THE 
  EARLY 
  STAGES 
  OF 
  WEST 
  AFRICAN 
  MOSQUITOS. 
  

  

  433 
  

  

  Thorax 
  broad, 
  about 
  1 
  mm. 
  in 
  mature 
  specimens, 
  moderately 
  well 
  clothed 
  with 
  

   hairs, 
  spines 
  not 
  very 
  highly 
  developed. 
  

  

  Abdomen 
  only 
  moderately 
  hairy, 
  bearing 
  numerous 
  small 
  single, 
  double 
  and 
  triple 
  

   hairs, 
  and 
  long 
  double 
  lateral 
  hairs 
  which 
  are 
  well 
  developed, 
  especially 
  on 
  the 
  

   anterior 
  segments. 
  Comb 
  composed 
  of 
  about 
  ten 
  spines 
  set 
  in 
  a 
  transverse 
  row, 
  

   the 
  spines 
  highly 
  chitinised, 
  sharply 
  pointed 
  — 
  but 
  the 
  extreme 
  tip 
  frequently 
  broken 
  

   off 
  — 
  and 
  with 
  very 
  small 
  secondary 
  barbs 
  hardly 
  visible, 
  except 
  with 
  high 
  powers 
  

   of 
  the 
  microscope 
  (fig. 
  19, 
  b). 
  The 
  siphonal 
  tuft 
  is 
  triple, 
  the 
  subsiphonal 
  composed 
  

   of 
  five 
  hairs, 
  and 
  the 
  anal 
  of 
  triple 
  hairs 
  ; 
  all 
  the 
  hairs 
  simple 
  or 
  very 
  slightly 
  

   pubescent. 
  Siphon 
  very 
  dark-coloured, 
  length 
  nearly 
  three 
  times 
  the 
  basal 
  width 
  

   (about 
  0-7 
  mm. 
  to 
  0-25 
  mm.). 
  The 
  pecten 
  extends 
  half 
  the 
  length 
  of 
  the 
  siphon 
  

   or 
  further 
  and 
  is 
  composed 
  of 
  about 
  eleven 
  to 
  thirteen 
  spines, 
  the 
  last 
  one 
  or 
  two 
  

   sometimes 
  outlying 
  ; 
  the 
  spines 
  are 
  sharply 
  pointed 
  and 
  with 
  very 
  small 
  secondary 
  

   barbs 
  hardly 
  visible 
  without 
  the 
  aid 
  of 
  high 
  objectives 
  of 
  the 
  microscope 
  (fig. 
  19, 
  c). 
  

   The 
  siphon 
  tuft 
  lies 
  just 
  beyond 
  the 
  last 
  spine 
  of 
  the 
  pecten 
  and 
  is 
  composed 
  of 
  a 
  

   single 
  or 
  double 
  stout 
  hair 
  ; 
  when 
  there 
  are 
  outlying 
  pecten 
  spines 
  the 
  tuft 
  is 
  proximal 
  

   to 
  them 
  and 
  thus 
  appears 
  to 
  lie 
  in 
  the 
  line 
  of 
  the 
  pecten. 
  Anal 
  segment 
  short 
  . 
  Papillae 
  

   long 
  and 
  broad, 
  with 
  rounded 
  ends 
  ; 
  all 
  four 
  equal 
  in 
  length 
  and 
  longer 
  than 
  the 
  anal 
  

   segment. 
  Beard 
  poorly 
  developed. 
  Dorsal 
  hairs 
  well 
  developed, 
  two 
  or 
  three 
  above 
  

   and 
  one 
  below 
  on 
  each 
  side. 
  On 
  each 
  side 
  of 
  the 
  anal 
  segment, 
  near 
  the 
  middle 
  of 
  

   its 
  posterior 
  margin, 
  is 
  a 
  long 
  single 
  or 
  more 
  usually 
  double 
  hair. 
  

  

  Fig. 
  19. 
  Aides 
  dendrophilus, 
  Edw. 
  : 
  a, 
  mental 
  plate 
  of 
  larva 
  

  

  scales 
  ; 
  d. 
  pupal 
  paddles. 
  

  

  b, 
  comb 
  scales 
  ; 
  c, 
  pecten 
  

  

  Diagnosis. 
  — 
  The 
  larva 
  resembles 
  in 
  some 
  respects 
  that 
  of 
  A. 
  (S.) 
  luteocephahis, 
  

   but 
  may 
  be 
  distinguished 
  from 
  it 
  by 
  the 
  characters 
  of 
  the 
  scales 
  of 
  the 
  pecten. 
  It 
  may 
  

   be 
  noted 
  in 
  this 
  connection 
  with 
  regard 
  to 
  A. 
  (S.) 
  luteocephahis 
  that 
  the 
  hook-like 
  

   spines 
  on 
  the 
  thorax 
  are 
  generally 
  rather 
  less 
  well 
  developed 
  than 
  those 
  of 
  A. 
  (S). 
  

   argenteus 
  and 
  rather 
  better 
  developed 
  than 
  those 
  of 
  A. 
  (5.) 
  dendrophilus 
  ; 
  that 
  the 
  

   comb-scales 
  when 
  highly 
  magnified 
  are 
  seen 
  to 
  be 
  finely 
  fringed 
  ; 
  that 
  the 
  siphonal 
  

   and 
  subsiphonal 
  tufts 
  when 
  similarly 
  magnified 
  are 
  seen 
  to 
  be 
  slightly 
  subplumose 
  

   and 
  more 
  so 
  than 
  those 
  of 
  A. 
  (S.) 
  dendrophilus 
  ; 
  and 
  that 
  the 
  hair 
  on 
  the 
  siphon 
  

   representing 
  the 
  tuft 
  is 
  sometimes 
  divided, 
  although 
  usually 
  single. 
  

  

  