﻿450 
  MALCOLM 
  E. 
  MACGREGOR 
  AND 
  S. 
  GEBERT. 
  

  

  they 
  are 
  seven 
  in 
  number 
  and 
  are 
  situated 
  as 
  follows 
  : 
  two 
  small 
  basal 
  ones, 
  the 
  

   second 
  a 
  little 
  larger 
  than 
  the 
  first, 
  the 
  third 
  one 
  having 
  a 
  white 
  dot 
  in 
  its 
  middle, 
  . 
  

   the 
  fourth 
  and 
  fifth 
  ones 
  united 
  on 
  the 
  auxiliary 
  vein 
  by 
  black 
  scales, 
  the 
  sixth 
  

   placed 
  obliquely, 
  the 
  seventh 
  near 
  the 
  apex 
  ; 
  the 
  other 
  veins 
  are 
  irregularly 
  spotted 
  

   with 
  white 
  scales, 
  the 
  last 
  vein 
  (costa) 
  which 
  bears 
  the 
  black 
  fringe 
  is 
  regularly 
  spotted 
  

   white 
  and 
  black 
  on 
  its 
  basal 
  half. 
  

  

  " 
  The 
  underside 
  of 
  the 
  body 
  bears 
  the 
  following 
  markings 
  : 
  — 
  Pleura 
  densely 
  

   covered 
  with 
  imbricated, 
  flat, 
  whitish 
  scales 
  ; 
  the 
  trochanters, 
  coxae, 
  and 
  the 
  base 
  of 
  

   the 
  femora 
  are 
  covered 
  with 
  white 
  scales 
  ; 
  the 
  ventral 
  segments 
  of 
  the 
  abdomen 
  are 
  

   spotted 
  basally 
  with 
  white 
  scales, 
  and 
  apically 
  with 
  a 
  well-defined, 
  narrow 
  white 
  line. 
  

  

  " 
  $.— 
  Proboscis 
  black, 
  with 
  a 
  few 
  scattered 
  white 
  scales, 
  and 
  a 
  white 
  band 
  just 
  

   below 
  the 
  first 
  anterior 
  third. 
  Palpi 
  longer 
  than 
  the 
  half 
  of 
  the 
  proboscis, 
  with 
  a 
  

   few 
  scattered 
  white 
  scales 
  and 
  white 
  bands 
  ; 
  the 
  apical 
  segment 
  bears 
  two 
  moderately 
  

   long 
  hairs. 
  Occiput 
  : 
  the 
  fore 
  part 
  of 
  the 
  occiput 
  is 
  covered 
  with 
  long, 
  narrow, 
  

   curved 
  white 
  scales 
  ; 
  the 
  hind 
  portion 
  with 
  yellow, 
  upright 
  forked 
  scales 
  ; 
  the 
  

   anterior 
  lateral 
  portions 
  with 
  black, 
  upright 
  forked 
  scales. 
  Scutellum 
  with 
  a 
  median 
  

   and 
  two 
  lateral 
  tufts 
  of 
  long 
  black 
  hairs, 
  and 
  a 
  few 
  long, 
  flat, 
  curved 
  white 
  scales. 
  

   Thorax 
  and 
  pleura 
  as 
  in 
  the 
  male. 
  Halteres 
  yellowish, 
  with 
  small 
  white 
  scales." 
  

  

  d'Emmerez 
  adds 
  : 
  " 
  The 
  larvae 
  of 
  this 
  species 
  were 
  found 
  by 
  Professor 
  Ronald 
  

   Ross 
  in 
  the 
  holes 
  of 
  trees 
  at 
  Vacoas 
  ; 
  and 
  although 
  the 
  larval 
  habitat 
  was 
  situate 
  

   near 
  dwellings 
  no 
  adults 
  were 
  seen 
  in 
  houses 
  or 
  verandahs. 
  This 
  well-marked 
  species 
  

   is 
  apparently 
  uncommon. 
  ..." 
  

  

  d'Emmerez's 
  description 
  of 
  the 
  adults 
  is 
  so 
  good 
  that 
  we 
  are 
  only 
  able 
  to 
  draw 
  

   attention 
  to 
  the 
  following 
  additional 
  characters 
  :— 
  

  

  (J. 
  — 
  Antennae 
  : 
  hairs 
  set 
  on 
  the 
  dorsal 
  and 
  ventral 
  aspects 
  of 
  the 
  segments 
  only 
  

   and 
  not 
  arranged 
  in 
  whorls. 
  Palpi 
  : 
  4th 
  segment 
  very 
  short 
  and 
  carrying 
  a 
  few 
  

   moderately 
  long 
  hairs. 
  Legs 
  : 
  2nd 
  tarsal 
  segments 
  of 
  the 
  middle 
  legs 
  often 
  with 
  a 
  

   few 
  white 
  scales 
  basally. 
  

  

  <$ 
  and 
  £. 
  — 
  Legs 
  : 
  hind 
  legs 
  abnormally 
  and 
  very 
  conspicuously 
  long, 
  trailing 
  

   behind 
  the 
  insect 
  and 
  lying 
  parallel 
  to 
  each 
  other 
  with 
  all 
  the 
  tarsal 
  joints 
  in 
  contact 
  

   with 
  the 
  surface 
  on 
  which 
  the 
  insect 
  rests, 
  instead 
  of 
  being 
  curved 
  upwards 
  and 
  raised 
  

   freely 
  in 
  the 
  air, 
  as 
  is 
  usual 
  in 
  mosquitos. 
  

  

  Observations 
  on 
  the 
  Larva. 
  

  

  Until 
  now 
  the 
  larva 
  has 
  remained 
  unknown. 
  We 
  have 
  found 
  that 
  the 
  larva 
  of 
  

   this 
  species, 
  notwithstanding 
  what 
  d'Emmerez 
  said 
  in 
  1908, 
  is 
  exceedingly 
  common, 
  

   frequenting 
  a 
  great 
  variety 
  of 
  tree-holes, 
  and 
  is 
  widely 
  distributed 
  over 
  the 
  island. 
  

   In 
  some 
  localities 
  it 
  is 
  almost 
  the 
  commonest 
  of 
  the 
  Mauritian 
  tree-hole 
  breeding 
  

   mosquitos. 
  

  

  Apparently 
  it 
  hibernates 
  as 
  a 
  larva, 
  as 
  we 
  have 
  been 
  able 
  to 
  watch 
  its 
  slow 
  develop- 
  

   ment 
  during 
  the 
  winter 
  months 
  in 
  tree-holes 
  that 
  have 
  been 
  advantageously 
  situated 
  

   near 
  the 
  laboratory. 
  Larvae 
  taken 
  from 
  these 
  tree-holes 
  and 
  kept 
  under 
  observation 
  

   in 
  the 
  laboratory 
  as 
  controls 
  have 
  shown 
  a 
  parallel 
  slow 
  development 
  — 
  the 
  tempera- 
  

   ture 
  of 
  the 
  laboratory 
  and 
  that 
  out 
  of 
  doors 
  being 
  practically 
  the 
  same. 
  Towards 
  

   the 
  end 
  of 
  winter 
  both 
  the 
  larvae 
  in 
  the 
  tree-holes 
  and 
  those 
  under 
  observation 
  

   indoors 
  finally 
  pupated. 
  

  

  The 
  types 
  of 
  tree-hole 
  water 
  in 
  which 
  this 
  species 
  have 
  been 
  found 
  have 
  varied 
  

   considerably. 
  Clear 
  tree-hole 
  water, 
  constantly 
  refreshed 
  by 
  rain 
  water 
  from 
  frequent 
  

   showers, 
  has 
  seemed 
  as 
  favourable 
  as 
  stale 
  dark 
  sherry-coloured 
  water 
  from 
  a 
  large 
  

   deep 
  hole 
  in 
  a 
  mango 
  tree. 
  The 
  only 
  difference 
  noted 
  being 
  that 
  in 
  the 
  clear 
  

   tree-hole 
  water 
  larvae 
  of 
  Aedes 
  albopictus 
  were 
  often 
  to 
  be 
  found 
  in 
  association, 
  

   whereas 
  in 
  the 
  dark 
  sherry-coloured 
  water 
  of 
  the 
  mango 
  tree 
  enormous 
  numbers 
  of 
  

   0. 
  arbor 
  icollis 
  larvae 
  were 
  alone 
  found. 
  

  

  