﻿THE 
  EARLY 
  STAGES 
  OF 
  WEST 
  AFRICAN 
  MOSQUITOS. 
  437 
  

  

  Head 
  large 
  but 
  not 
  highly 
  chitinised 
  ; 
  length 
  about 
  0-9 
  mm., 
  greatest 
  breadth 
  

   about 
  1-3 
  mm. 
  Antenna 
  slightly 
  curved 
  and 
  bearing 
  at 
  about 
  two-thirds 
  of 
  its 
  

   length 
  a 
  large 
  tuft 
  of 
  plumose 
  hairs. 
  The 
  portion 
  of 
  the 
  shaft 
  distal 
  to 
  the 
  tuft 
  

   is 
  very 
  dark-coloured 
  and 
  highly 
  chitinised. 
  There 
  are 
  numerous 
  spicules 
  on 
  the 
  

   shaft, 
  those 
  on 
  the 
  pale 
  basal 
  portion 
  slender, 
  those 
  on 
  the 
  dark 
  apical 
  portion 
  stouter. 
  

   At 
  the 
  end 
  of 
  the 
  antenna 
  are 
  three 
  long, 
  stout, 
  dark 
  hairs 
  which 
  are 
  simple, 
  and 
  not 
  

   pubescent 
  as 
  they 
  are 
  in 
  C. 
  guiarti, 
  a 
  short 
  spine-like 
  dark 
  hair 
  with 
  smaller 
  spines 
  

   at 
  its 
  base, 
  and 
  a 
  small, 
  less 
  highly 
  chitinised 
  cylindrical 
  organ, 
  which 
  apparently 
  is 
  

   the 
  " 
  spine 
  " 
  that 
  Wesche 
  notes 
  as 
  being 
  " 
  very 
  liable 
  to 
  injury." 
  The 
  post-antennal 
  

   hairs 
  (to 
  use 
  the 
  terms 
  employed 
  by 
  Lang) 
  are 
  well-developed 
  tufts 
  of 
  plumose 
  hairs, 
  

   the 
  outer 
  composed 
  of 
  about 
  a 
  dozen 
  hairs, 
  the 
  longest 
  of 
  which 
  extend 
  beyond 
  the 
  

   middle 
  of 
  the 
  antenna, 
  the 
  middle 
  composed 
  of 
  two 
  or 
  three 
  and 
  the 
  inner 
  of 
  three 
  

   to 
  five 
  hairs. 
  In 
  C. 
  guiarti 
  the 
  middle 
  and 
  inner 
  tufts 
  are 
  each 
  composed 
  of 
  two 
  hairs. 
  

   The 
  mental 
  plate 
  has 
  a 
  large, 
  rather 
  bluntly-pointed 
  central 
  tooth, 
  with 
  a 
  closely 
  

   applied 
  small 
  tooth 
  and 
  more 
  externally 
  five 
  more 
  widely 
  separated 
  teeth 
  on 
  each 
  side. 
  

  

  Thorax 
  not 
  so 
  wide 
  as 
  the 
  head 
  ; 
  it 
  has 
  well 
  developed 
  lateral 
  tufts 
  of 
  plumose 
  

   or 
  subplumose 
  hairs 
  and 
  long 
  hairs 
  projecting 
  over 
  the 
  head. 
  

  

  Abdomen. 
  The 
  lateral 
  abdominal 
  hairs 
  appear 
  to 
  be 
  triple 
  on 
  all 
  the 
  segments 
  

   but 
  are 
  strongly 
  developed 
  on 
  the 
  first 
  two 
  segments 
  only. 
  Curious 
  dendritic 
  tufts, 
  

   most 
  strongly 
  developed 
  on 
  the 
  posterior 
  segments, 
  are 
  also 
  present. 
  The 
  siphonal, 
  

   subsiphonal 
  and 
  anal 
  tufts 
  are 
  well 
  developed, 
  the 
  hairs 
  composing 
  the 
  two 
  first 
  

   being 
  plumose, 
  those 
  composing 
  the 
  last 
  apparently 
  pubescent 
  or 
  simple. 
  The 
  comb 
  

   is 
  made 
  up 
  of 
  about 
  fourteen 
  to 
  twenty 
  pointed 
  and 
  fringed 
  scales 
  arranged 
  in 
  an 
  

   irregular 
  patch. 
  The 
  siphon 
  is 
  about 
  twelve 
  to 
  fourteen 
  times 
  as 
  long 
  as 
  the 
  diameter 
  

   of 
  its 
  base, 
  tapering 
  slightly 
  in 
  the 
  basal 
  quarter 
  but 
  thereafter 
  almost 
  uniformly 
  

   cylindrical. 
  The 
  pecten 
  is 
  composed 
  of 
  six 
  to 
  nine 
  simple 
  spines 
  confined 
  to 
  the 
  

   basal 
  seventh 
  of 
  the 
  siphon. 
  Distal 
  to 
  the 
  pecten 
  are 
  several 
  pairs 
  of 
  very 
  delicate 
  

   small 
  hair-tufts, 
  each 
  composed 
  of 
  two 
  or 
  three 
  hairs. 
  Anal 
  segment 
  slightly 
  longer 
  

   than 
  broad 
  with 
  papillae 
  equal, 
  long, 
  slender, 
  and 
  pointed 
  at 
  their 
  extremities, 
  

   exceeding 
  the 
  anal 
  segment 
  slightly 
  in 
  length. 
  The 
  beard 
  is 
  moderately 
  well 
  developed, 
  

   its 
  constituent 
  hairs 
  rather 
  longer 
  than 
  the 
  papillae. 
  Dorsal 
  hairs 
  at 
  the 
  posterior 
  

   margin 
  of 
  the 
  anal 
  segment 
  four 
  to 
  six 
  above 
  and 
  a 
  single 
  longer 
  hair 
  below 
  on 
  

   each 
  side. 
  

  

  Diagnosis. 
  — 
  This 
  larva 
  bears 
  a 
  general 
  resemblance 
  to 
  that 
  of 
  C. 
  guiarti, 
  but 
  may 
  

   be 
  distinguished 
  from 
  it 
  by 
  numerous 
  characters, 
  such 
  as 
  those 
  of 
  the 
  post-antennal 
  

   hairs 
  on 
  the 
  head, 
  the 
  number 
  of 
  spines 
  in 
  the 
  comb 
  and 
  pecten 
  and 
  the 
  dorsal 
  hairs 
  

   on 
  the 
  anal 
  segment. 
  These 
  differences 
  are 
  notable 
  and 
  appear 
  to 
  indicate 
  that 
  the 
  

   two 
  mosquitos 
  are 
  distinct 
  and 
  not 
  merely 
  varieties 
  of 
  a 
  single 
  species. 
  

  

  Pupa.— 
  The 
  pupa 
  is 
  greenish 
  in 
  colour, 
  and 
  resembles 
  that 
  of 
  C. 
  guiarti, 
  but 
  

   is 
  more 
  highly 
  chitinised. 
  

  

  Cephalothorax. 
  The 
  respiratory 
  trumpets 
  (fig. 
  22, 
  a) 
  are 
  long 
  and 
  slender, 
  their 
  

   basal 
  halves 
  dark 
  and 
  highly 
  chitinised, 
  and 
  their 
  distal 
  ends 
  with 
  narrow 
  apertures. 
  

   Their 
  length 
  is 
  about 
  0-85 
  mm. 
  and 
  the 
  ratio 
  of 
  the 
  length 
  of 
  the 
  meatus 
  to 
  the 
  total 
  

   length 
  of 
  the 
  trumpet 
  is 
  about 
  1 
  to 
  1-1. 
  The 
  cephalothoracic 
  setae 
  are 
  mostly 
  

   inconspicuous 
  and 
  call 
  for 
  no 
  special 
  comment. 
  The 
  postero-thoracic 
  setae, 
  however, 
  

   are 
  small, 
  each 
  composed 
  of 
  two 
  hairs, 
  whereas 
  in 
  C. 
  guiarti 
  apparently 
  the 
  internal 
  

   one 
  is 
  composed 
  of 
  about 
  five 
  and 
  the 
  external 
  of 
  three 
  hairs. 
  

  

  Abdomen 
  (fig. 
  22, 
  b). 
  The 
  paddles 
  are 
  of 
  moderate 
  size, 
  length 
  about 
  0-8 
  mm., 
  

   greatest 
  breadth 
  about 
  0-6 
  ram: 
  The 
  external 
  buttress 
  is 
  rather 
  slender 
  and 
  is 
  

   denticulated, 
  the 
  midrib 
  being 
  somewhat 
  more 
  substantial. 
  There 
  is 
  no 
  fringe. 
  The 
  

   hairs 
  at 
  the 
  distal 
  extremity 
  of 
  the 
  midrib 
  are 
  very 
  small. 
  The 
  abdominal 
  setae 
  are 
  

   similar 
  to 
  those 
  of 
  C. 
  guiarti. 
  The 
  lateral 
  setae 
  on 
  segment 
  viii 
  are 
  small 
  tufts, 
  about 
  

   one-quarter 
  to 
  one-third 
  of 
  the 
  length 
  of 
  the 
  paddles, 
  composed 
  of 
  seven 
  to 
  nine 
  

  

  (84SS) 
  2 
  H 
  

  

  