﻿EARLY 
  STAGES 
  OF 
  WEST 
  AFRICAN 
  MOSQUITOS. 
  63 
  

  

  The 
  paddles, 
  which 
  are 
  about 
  1 
  mm. 
  long, 
  are 
  broad, 
  the 
  ratio 
  of 
  length 
  to 
  

   greatest 
  breadth 
  being 
  about 
  1*2 
  to 
  1 
  ; 
  they 
  are 
  supported 
  by 
  an 
  external 
  buttress 
  

   and 
  a 
  moderately 
  well 
  developed 
  midrib. 
  At 
  the 
  end 
  of 
  the 
  midrib 
  is 
  the 
  usual 
  

   long 
  single 
  hair, 
  which 
  is 
  about 
  one- 
  eighth 
  the 
  length 
  of 
  the 
  paddle. 
  The 
  paddles 
  

   are 
  devoid 
  of 
  a 
  fringe. 
  

  

  At 
  the 
  posterior 
  angle 
  of 
  the 
  8th 
  abdominal 
  segment 
  is 
  a 
  tuft 
  of 
  7 
  to 
  8 
  subplumose 
  

   hairs, 
  of 
  which 
  one 
  or 
  two 
  may 
  be 
  branched. 
  This 
  tuft 
  is 
  short, 
  about 
  one-fifth 
  

   the 
  length 
  of 
  the 
  paddle. 
  

  

  A 
  little 
  above 
  the 
  posterior 
  angle 
  of 
  the 
  7th 
  segment 
  is 
  a 
  tuft 
  of 
  3 
  or 
  4 
  pubescent 
  

   hairs 
  ; 
  this 
  tuft 
  is 
  about 
  one-sixth 
  the 
  length 
  of 
  the 
  paddle. 
  In 
  a 
  similar 
  position 
  

   on 
  the 
  6th, 
  5th 
  and 
  4th 
  segments 
  there 
  is 
  a 
  single 
  hair, 
  sometimes 
  divided. 
  

  

  In 
  addition 
  to 
  the 
  tufts 
  and 
  hairs, 
  already 
  described, 
  there 
  are 
  on 
  the 
  dorsal 
  

   aspect 
  of 
  the 
  abdomen 
  numerous 
  small 
  and 
  delicate 
  hairs, 
  most 
  of 
  which 
  are 
  quite 
  

   inconspicuous 
  ; 
  those 
  situated 
  in 
  the 
  positions 
  corresponding 
  to 
  the 
  outer 
  lateral 
  

   row 
  on 
  the 
  4th 
  to 
  the 
  6th 
  segments 
  are, 
  however, 
  better 
  developed, 
  and 
  are 
  long 
  

   double 
  or 
  triple 
  hairs. 
  On 
  the 
  same 
  segments 
  in 
  the 
  positions 
  corresponding 
  to 
  

   the 
  inner 
  lateral 
  row 
  are 
  small 
  tufts 
  of 
  delicate 
  hairs. 
  The 
  hairs 
  on 
  the 
  posterior 
  

   margins 
  of 
  the 
  7th 
  segment 
  are 
  all 
  small. 
  On 
  the 
  posterior 
  margin 
  of 
  the 
  3rd 
  segment 
  

   is 
  a 
  small 
  tuft 
  in 
  line 
  with 
  the 
  inner 
  lateral 
  row, 
  and 
  a 
  single 
  hair 
  of 
  moderate 
  length 
  

   a 
  little 
  above 
  and 
  external 
  to 
  it. 
  The 
  dendritic 
  hairs 
  or 
  tufts 
  on 
  the 
  1st 
  and 
  2nd 
  

   segments 
  are 
  moderately 
  well 
  developed. 
  

  

  The 
  respiratory 
  trumpets 
  are 
  about 
  '7 
  mm. 
  long 
  ; 
  they 
  are 
  rather 
  broad, 
  and 
  

   have 
  wide 
  apertures. 
  The 
  ratio 
  of 
  the 
  length 
  of 
  the 
  closed 
  portion, 
  the 
  meatus, 
  

   to 
  the 
  total 
  length 
  of 
  the 
  trumpet 
  is 
  about 
  1 
  to 
  1*5. 
  

  

  Diagnosis. 
  — 
  See 
  0. 
  nigeriensis 
  (p. 
  ). 
  

  

  Habitat. 
  — 
  The 
  two 
  pupae 
  on 
  which 
  the 
  above 
  description 
  is 
  based 
  were 
  found 
  

   in 
  a 
  collection 
  of 
  rain-water 
  in 
  a 
  disused 
  kerosene 
  tin 
  at 
  Accra, 
  Gold 
  Coast, 
  ll.xii.17. 
  

   The 
  tin 
  was 
  partly 
  concealed 
  by 
  vegetation. 
  

  

  Ochlerotatus 
  nigeriensis, 
  Theo. 
  

  

  Larva. 
  — 
  The 
  larva 
  of 
  this 
  mosquito 
  is 
  included 
  by 
  Edwards 
  in 
  his 
  " 
  Revised 
  Keys 
  

   to 
  the 
  Known 
  Larvae 
  of 
  African 
  Culicinae 
  " 
  (loc.cit., 
  pp. 
  376 
  and 
  377), 
  and 
  is 
  figured 
  

   by 
  him. 
  

  

  Pupa 
  (fig. 
  4).— 
  The 
  pupa 
  is 
  of 
  moderate 
  size, 
  measuring 
  about 
  5 
  to 
  6 
  mm. 
  when 
  

   extended, 
  and 
  is 
  very 
  strongly 
  chitinised. 
  

  

  The 
  paddles, 
  which 
  are 
  nearly 
  1 
  mm. 
  long, 
  are 
  broad, 
  the 
  ratio 
  of 
  length 
  to 
  greatest 
  

   breadth 
  being 
  about 
  1*2 
  to 
  1 
  ; 
  they 
  are 
  supported 
  by 
  a 
  midrib 
  and 
  by 
  an 
  external 
  

   buttress, 
  which, 
  however, 
  is 
  not 
  conspicuous. 
  Near 
  the 
  end 
  of 
  the 
  midrib 
  is 
  the 
  

   usual 
  long 
  single 
  hair, 
  measuring 
  in 
  this 
  species 
  about 
  one-eighth 
  the 
  length 
  of 
  the 
  

   paddle. 
  The 
  paddles 
  have 
  no 
  fringe, 
  but 
  may 
  show 
  a 
  few 
  minute 
  teeth, 
  especially 
  

   about 
  the 
  middle 
  of 
  the 
  external 
  border 
  ; 
  these 
  teeth 
  are 
  too 
  inconspicuous 
  to 
  show 
  in 
  

   the 
  figure. 
  

  

  At 
  the 
  posterior 
  angle 
  of 
  the 
  8th 
  abdominal 
  segment 
  is 
  a 
  tuft 
  of 
  about 
  six 
  (5 
  to 
  7) 
  

   hairs 
  which 
  are 
  subplumose 
  at 
  their 
  bases 
  and 
  sometimes 
  branched 
  towards 
  their 
  

   tips. 
  This 
  tuft 
  is 
  short, 
  its 
  length 
  being 
  about 
  one-fifth 
  the 
  length 
  of 
  the 
  paddle. 
  

  

  