﻿THE 
  EARLY 
  STAGES 
  OF 
  WEST 
  AFRICAN 
  MOSQUITOS. 
  435 
  

  

  a 
  short 
  distance 
  above 
  the 
  base. 
  They 
  are 
  about 
  1 
  -1 
  mm. 
  long, 
  and 
  the 
  ratio 
  of 
  the 
  

   length 
  of 
  the 
  meatus 
  to 
  the 
  total 
  length 
  is 
  about 
  1 
  to 
  1 
  -3. 
  The 
  cephalothoracic 
  setae 
  

   are 
  mostly 
  small 
  and 
  inconspicuous, 
  but 
  the 
  internal 
  postero-thoracic 
  seta 
  is 
  a 
  rather 
  

   conspicuous 
  tuft 
  of 
  about 
  six 
  subplumose 
  hairs. 
  

  

  Abdomen. 
  The 
  paddles 
  are 
  infuscated 
  and 
  very 
  broad 
  ; 
  length 
  about 
  1-0 
  mm., 
  

   greatest 
  breadth 
  about 
  0-85 
  mm. 
  The 
  midrib 
  and 
  external 
  buttress 
  are 
  moderately 
  

   well 
  developed, 
  the 
  latter 
  extending 
  more 
  than 
  half 
  the 
  length 
  of 
  the 
  paddles. 
  The 
  

   infuscation 
  is 
  most 
  marked 
  at 
  the 
  distal 
  end 
  and 
  to 
  the 
  inner 
  side 
  of 
  the 
  midrib. 
  

   The 
  hairs 
  at 
  the 
  end 
  of 
  the 
  midrib 
  are 
  two, 
  both 
  very 
  small 
  (25 
  ft 
  to 
  30 
  p), 
  but 
  the 
  

   one 
  stouter 
  than 
  the 
  other 
  and 
  subdivided 
  at 
  its 
  end. 
  There 
  is 
  no 
  fringe, 
  but 
  the 
  

   external 
  buttress 
  bears 
  a 
  few 
  minute 
  denticules. 
  

  

  The 
  abdominal 
  setae 
  are 
  generally 
  similar 
  to 
  those 
  of 
  Calex 
  bitaeniorhynchits. 
  

   The 
  lateral 
  setae 
  on 
  segment 
  viii 
  are 
  small 
  tufts, 
  about 
  one-quarter 
  the 
  length 
  of 
  

   the 
  paddle, 
  composed 
  of 
  five 
  stout, 
  subplumose 
  hairs 
  : 
  on 
  segment 
  vii 
  similar 
  tufts 
  

   of 
  three 
  hairs 
  ; 
  on 
  segments 
  vi 
  and 
  v 
  long 
  (0-4 
  mm.), 
  stout, 
  single 
  setae 
  ; 
  and 
  on 
  

   segment 
  iv 
  reduced 
  to 
  shorter, 
  delicate, 
  single 
  setae. 
  The 
  sublateral 
  setae 
  on 
  the 
  

   dorsum 
  on 
  segments 
  vi 
  and 
  v 
  are 
  long, 
  strong, 
  double 
  setae 
  reaching 
  right 
  across 
  the 
  

   succeeding 
  segment 
  ; 
  on 
  segment 
  vii 
  single, 
  more 
  delicate 
  and 
  smaller, 
  reaching 
  only 
  

   about 
  half-way 
  across 
  the 
  eighth 
  segment 
  ; 
  on 
  segment 
  iv 
  tufts 
  of 
  three 
  long 
  hairs. 
  

   The 
  submedian 
  setae 
  increase 
  in 
  size 
  from 
  behind 
  forwards 
  ; 
  on 
  segments 
  vii 
  and 
  vi 
  

   they 
  are 
  single 
  hairs 
  ; 
  on 
  segments 
  v, 
  iv 
  and 
  iii 
  tufts 
  of 
  two 
  to 
  three, 
  four 
  to 
  five, 
  

   and 
  about 
  seven 
  hairs 
  respectively. 
  The 
  dendritic 
  tufts 
  on 
  segment 
  i 
  are 
  well 
  

   developed. 
  The 
  other 
  abdominal 
  setae 
  do 
  not 
  call 
  for 
  special 
  mention. 
  

  

  Diagnosis. 
  — 
  This 
  pupa 
  resembles 
  closely 
  that 
  of 
  C. 
  bitaeniorhynchus, 
  but 
  may 
  be 
  

   distinguished 
  from 
  it, 
  apparently, 
  by 
  the 
  narrower 
  opening 
  of 
  the 
  respiratory 
  

   trumpets 
  (fig. 
  20). 
  Further 
  material 
  is 
  required 
  to 
  confirm 
  any 
  small 
  differences 
  

   there 
  may 
  be 
  in 
  the 
  cephalothoracic 
  and 
  abdominal 
  setae. 
  

  

  Habitat. 
  — 
  Accra, 
  26.ix.1921, 
  found 
  in 
  pools 
  on 
  the 
  western 
  side 
  of 
  Korley 
  Gona. 
  

  

  Fig. 
  20. 
  Pupal 
  trumpets 
  of 
  : 
  a, 
  Culcx 
  ammlioris, 
  

   Theo. 
  ; 
  b, 
  C. 
  bitaeniorhynchus, 
  Theo. 
  

  

  Culex 
  ingrami, 
  Edw. 
  

  

  Larva. 
  — 
  The 
  larva 
  of 
  this 
  mosquito 
  has 
  already 
  been 
  described 
  (Bull. 
  Ent. 
  Res. 
  

   vii, 
  pp. 
  11-12). 
  

  

  Pupa. 
  — 
  The 
  pupa, 
  of 
  which 
  only 
  a 
  single 
  specimen 
  was 
  examined, 
  is 
  rather 
  

   feebly 
  chitinised 
  and 
  has 
  long 
  slender 
  respiratory 
  trumpets 
  (fig. 
  21, 
  a) 
  and 
  long 
  

   sublateral 
  setae 
  on 
  the 
  dorsal 
  aspect 
  of 
  the 
  fifth 
  and 
  sixth 
  abdominal 
  segments. 
  

  

  Cephalothorax. 
  The 
  respiratory 
  trumpets 
  are 
  long 
  and 
  slender 
  tubes 
  with 
  an 
  

   infuscated 
  band 
  a 
  little 
  above 
  their 
  bases, 
  and 
  with 
  narrow 
  apertures. 
  Their 
  length 
  

   is 
  about 
  0-6 
  mm., 
  their 
  width 
  in 
  the 
  middle 
  about 
  95 
  p, 
  and 
  the 
  length 
  of 
  the 
  apertures 
  

   (pinna) 
  about 
  93 
  p 
  ; 
  the 
  ratio 
  of 
  the 
  length 
  of 
  the 
  meatus 
  to 
  the 
  total 
  length 
  is 
  nearly 
  

  

  