﻿291 
  

  

  CERTAIN 
  NURSERIES 
  OF 
  INSECT 
  LIFE 
  IN 
  WEST 
  AFRICA. 
  

   By 
  J. 
  W. 
  S. 
  Macfie 
  and 
  A. 
  Ingram. 
  

  

  When 
  studying 
  the 
  bionomics 
  of 
  certain 
  species 
  of 
  the 
  Ceratopogoninae 
  in 
  the 
  

   Gold 
  Coast, 
  samples 
  of 
  material 
  collected 
  from 
  different 
  sources, 
  where 
  it 
  seemed 
  

   likely 
  that 
  the 
  early 
  stages 
  of 
  these 
  small 
  insects 
  might 
  be 
  passed, 
  were 
  brought 
  to 
  

   the 
  laboratory 
  for 
  examination. 
  The 
  samples 
  were 
  chiefly 
  taken 
  from 
  rot-holes 
  in 
  

   live 
  trees, 
  from 
  cut 
  bamboo 
  stumps, 
  from 
  decaying 
  logs, 
  from 
  old 
  canoes, 
  from 
  the 
  

   edges 
  of 
  pools 
  and 
  puddles, 
  from 
  crab-holes, 
  and 
  from 
  the 
  bases 
  of 
  banana 
  plants. 
  

  

  Each 
  sample 
  on 
  arrival 
  was 
  placed 
  in 
  a 
  wide-mouthed 
  glass 
  jar, 
  and 
  — 
  the 
  mouth 
  

   of 
  the 
  jar 
  having 
  been 
  covered 
  with 
  a 
  glass 
  plate 
  — 
  was 
  kept 
  under 
  observation 
  for 
  

   at 
  least 
  seven 
  days, 
  after 
  which 
  period, 
  if 
  no 
  insect 
  had 
  hatched 
  and 
  no 
  larva 
  or 
  pupa 
  

   had 
  been 
  seen, 
  it 
  was 
  thrown 
  away. 
  Experience 
  having 
  proved 
  that 
  dry 
  samples 
  were 
  

   unproductive 
  of 
  insects, 
  and 
  that 
  complete 
  submergence 
  of 
  the 
  material 
  in 
  water 
  

   drowned 
  certain 
  larvae, 
  it 
  was 
  found 
  necessary 
  to 
  arrange 
  the 
  samples 
  in 
  the 
  jars 
  in 
  

   such 
  a 
  way 
  that 
  they 
  were 
  damp 
  but 
  did 
  not 
  become 
  water-logged. 
  This 
  was 
  effected 
  

   by 
  pouring 
  water 
  into 
  the 
  jars 
  to 
  a 
  depth 
  of 
  a 
  quarter 
  to 
  half 
  an 
  inch, 
  and 
  by 
  heaping 
  

   up 
  the 
  material 
  at 
  one 
  side 
  ; 
  in 
  this 
  way 
  it 
  was 
  possible 
  to 
  rear 
  terrestrial 
  and 
  aquatic 
  

   larvae 
  simultaneously. 
  Many 
  of 
  the 
  samples 
  proved 
  barren 
  ; 
  on 
  the 
  other 
  hand, 
  those 
  

   from 
  certain 
  sources 
  were 
  found 
  to 
  be 
  teeming 
  with 
  insect 
  life. 
  The 
  most 
  productive 
  

   material 
  examined 
  was 
  banana 
  fibre 
  in 
  a 
  state 
  of 
  decomposition, 
  such 
  as 
  can 
  readily 
  

   be 
  found 
  at 
  the 
  base 
  of 
  most 
  mature 
  banana 
  plants 
  ; 
  the 
  fibre 
  must 
  be 
  of 
  a 
  brown 
  hue 
  

   and 
  somewhat 
  softened, 
  hard 
  cream-coloured 
  fibre 
  having 
  been 
  found 
  to 
  yield 
  so 
  few 
  

   insects 
  as 
  scarcely 
  to 
  be 
  worth 
  the 
  trouble 
  of 
  collection. 
  How 
  prolific 
  of 
  insect 
  life 
  

   such 
  decaying 
  banana 
  fibre 
  can 
  be, 
  may 
  be 
  judged 
  from 
  the 
  fact 
  that 
  over 
  a 
  hundred 
  

   specimens 
  of 
  Ceratopogoninae 
  alone, 
  comprising 
  at 
  least 
  five 
  species, 
  were 
  obtained 
  

   from 
  a 
  single 
  sample 
  of 
  this 
  material, 
  which 
  weighed 
  about 
  1^ 
  lb., 
  in 
  the 
  course 
  of 
  five 
  

   weeks 
  during 
  which 
  it 
  was 
  under 
  observation. 
  Next 
  in 
  productiveness 
  to 
  banana 
  

   fibre 
  were 
  the 
  debris 
  collected 
  from 
  rot-holes 
  in 
  live 
  trees 
  and 
  the 
  rotting 
  wood 
  scraped 
  

   from 
  the 
  ends 
  and 
  sides 
  of 
  old 
  canoes 
  tied 
  to 
  the 
  bank 
  of 
  the 
  river 
  Densu 
  at 
  a 
  village 
  

   called 
  Oblogo. 
  

  

  As 
  such 
  samples 
  yielded 
  not 
  only 
  Ceratopogoninae, 
  but 
  also 
  other 
  insects, 
  it 
  

   may 
  be 
  of 
  interest 
  to 
  give 
  lists 
  of 
  the 
  insects 
  which 
  hatched 
  from 
  them, 
  merely 
  as 
  a 
  

   suggestion 
  of 
  the 
  wonderful 
  assemblage 
  of 
  insect 
  life 
  which 
  may 
  be 
  found 
  in 
  small 
  

   quantities 
  of 
  decaying 
  vegetable 
  matter 
  in 
  West 
  Africa. 
  It 
  is 
  to 
  be 
  noted 
  that 
  banana 
  

   fibre 
  and 
  the 
  rotting 
  wood 
  at 
  the 
  sides 
  and 
  ends 
  of 
  canoes 
  are 
  normally 
  habitats 
  of 
  

   terrestrial 
  larvae, 
  though 
  occasionally 
  they 
  may 
  become 
  suitable 
  for 
  aquatic 
  larvae, 
  

   as, 
  for 
  example, 
  when 
  the 
  stem 
  of 
  a 
  banana 
  plant 
  has 
  been 
  cut 
  through 
  and 
  the 
  

   hollow 
  becomes 
  filled 
  with 
  water, 
  or 
  when 
  a 
  canoe 
  becomes 
  filled 
  with 
  rain-water. 
  

  

  