﻿INTRODUCING 
  SCOLIID 
  WASPS 
  FROM 
  MADAGASCAR 
  TO 
  MAURITIUS. 
  251 
  

  

  they 
  were 
  caught 
  were 
  transferred 
  into 
  small 
  portable 
  laboratory 
  breeding-cages, 
  

   the 
  internal 
  dimensions 
  of 
  which 
  were 
  30 
  in. 
  in 
  height 
  and 
  25 
  in. 
  in 
  length 
  and 
  

   breadth. 
  The 
  sides 
  and 
  tops 
  were 
  of 
  wire 
  gauze, 
  while 
  the 
  bottom 
  was 
  covered 
  with 
  

   soil. 
  When, 
  as 
  often 
  happened, 
  trees 
  had 
  to 
  be 
  climbed 
  to 
  capture 
  Scoliids, 
  the 
  

   insects 
  were 
  placed 
  for 
  the 
  time 
  being 
  in 
  stoppered 
  tubes 
  kept 
  in 
  the 
  pocket 
  and 
  

   transferred 
  later 
  to 
  the 
  laboratory 
  cages. 
  As 
  we 
  often 
  remained 
  away 
  from 
  our 
  

   starting-place 
  for 
  more 
  than 
  two 
  days, 
  the 
  insects 
  had 
  to 
  remain 
  during 
  this 
  time 
  

   in 
  the 
  small 
  cages, 
  which 
  at 
  times 
  contained 
  over 
  50 
  Scoliids. 
  

  

  As 
  can 
  be 
  gathered 
  from 
  this 
  procedure 
  and 
  from 
  the 
  difficulties 
  necessarily 
  

   attending 
  the 
  transport 
  of 
  Wardian 
  cases 
  — 
  e.g., 
  embarkation 
  in 
  a 
  rough 
  sea, 
  tranship- 
  

   ment, 
  overcrowding, 
  landing 
  in 
  Mauritius, 
  and 
  finally 
  the 
  transport 
  of 
  the 
  cages 
  

   20 
  miles 
  away 
  from 
  the 
  landing-place 
  for 
  ultimate 
  liberation 
  — 
  the 
  insects 
  were 
  

   handled 
  a 
  great 
  number 
  of 
  times 
  and 
  were 
  often 
  kept 
  under 
  conditions 
  most 
  

   unfavourable 
  to 
  their 
  welfare, 
  and 
  it 
  is 
  surprising 
  that 
  the 
  death-rate 
  was 
  not 
  higher. 
  

   Actually, 
  of 
  1,033 
  insects 
  shipped, 
  805 
  were 
  landed 
  alive 
  in 
  Mauritius. 
  

  

  Before 
  transferring 
  the 
  insects 
  to 
  the 
  Wardian 
  cases 
  these 
  had 
  been 
  amply 
  stocked 
  

   with 
  Oryctes 
  larvae, 
  which 
  were 
  allowed 
  to 
  bury 
  themselves 
  in 
  a 
  layer 
  of 
  soil 
  and 
  

   bits 
  of 
  decaying 
  wood 
  that 
  had 
  been 
  placed 
  in 
  the 
  bottom 
  of 
  the 
  case. 
  As 
  food 
  for 
  

   the 
  wasps 
  honey 
  was 
  used. 
  The 
  honey 
  container 
  consisted 
  of 
  a 
  block 
  of 
  wood 
  in 
  

   which 
  several 
  holes 
  had 
  been 
  bored. 
  These 
  were 
  filled 
  with 
  honey 
  and 
  the 
  block 
  

   placed 
  in 
  the 
  soil 
  contained 
  in 
  the 
  cages 
  every 
  afternoon 
  after 
  the 
  insects 
  had 
  dug 
  

   themselves 
  in. 
  

  

  It 
  seems 
  from 
  experience 
  that 
  if 
  it 
  is 
  desired 
  to 
  bring 
  about 
  reproduction 
  en 
  route 
  

   the 
  best 
  plan 
  would 
  be 
  to 
  confine 
  the 
  insects 
  in 
  separate 
  earthenware 
  pots 
  covered 
  

   with 
  a 
  wire 
  gauze 
  cylinder 
  and 
  containing 
  only 
  an 
  appropriate 
  number 
  of 
  larvae. 
  

  

  Laboratory 
  Experiments. 
  

  

  Preliminary 
  investigations 
  in 
  Madagascar 
  showed 
  that 
  Scolia 
  oryctophaga 
  was 
  

   capable 
  of 
  successfully 
  parasitising 
  Oryctes 
  tarandus 
  ; 
  breeding 
  experiments 
  were 
  

   conducted 
  in 
  the 
  insectary 
  at 
  Reduit 
  with 
  these 
  two 
  insects 
  after 
  the 
  return 
  from 
  

   Madagascar. 
  The 
  method 
  of 
  working 
  adopted 
  was 
  to 
  breed 
  the 
  insects 
  in 
  large 
  

   earthenware 
  pots 
  30 
  cm. 
  in 
  diameter 
  and 
  25 
  cm. 
  deep 
  at 
  the 
  centre. 
  These 
  were 
  

   filled 
  with 
  soil 
  to 
  a 
  depth 
  of 
  10 
  cm. 
  from 
  the 
  top. 
  Bits 
  of 
  cane 
  were 
  buried 
  at 
  various 
  

   depths 
  in 
  the 
  soil 
  to 
  serve 
  as 
  food 
  for 
  larvae 
  of 
  Oryctes 
  tarandus, 
  which 
  were 
  placed 
  in 
  

   the 
  pot 
  and 
  allowed 
  to 
  dig 
  themselves 
  in. 
  The 
  pots 
  were 
  each 
  covered 
  with 
  a 
  wire 
  

   gauze 
  cylinder 
  fitted 
  with 
  a 
  lid 
  on 
  the 
  top. 
  

  

  After 
  the 
  Scoliids 
  had 
  been 
  inserted 
  into 
  the 
  pots 
  the 
  contents 
  were 
  examined 
  

   every 
  five 
  or 
  six 
  days. 
  As 
  soon 
  as 
  a 
  larva 
  had 
  become 
  parasitised 
  it 
  was 
  removed 
  

   to 
  the 
  laboratory 
  and 
  placed 
  in 
  an 
  artificial 
  cell 
  in 
  a 
  large 
  Petri 
  dish 
  covered 
  with 
  a 
  

   bell-jar, 
  on 
  the 
  sides 
  of 
  which 
  black 
  paper 
  had 
  been 
  pasted 
  to 
  intercept 
  the 
  light. 
  

   The 
  cells 
  were 
  made 
  by 
  filling 
  the 
  Petri 
  dish 
  with 
  moist 
  earth 
  up 
  to 
  the 
  rim 
  and 
  then 
  

   pressing 
  down 
  upon 
  the 
  soil 
  with 
  the 
  thumb 
  so 
  as 
  to 
  form 
  a 
  cavity, 
  in 
  which 
  the 
  

   parasitised 
  larva 
  was 
  laid. 
  As 
  soon 
  as 
  the 
  larval 
  parasite 
  was 
  full-grown 
  and 
  had 
  

   removed 
  its 
  neck 
  from 
  the 
  body 
  of 
  the 
  grub, 
  a 
  cover 
  was 
  moulded 
  out 
  of 
  clay 
  soil 
  and 
  

   placed 
  on 
  the 
  cell 
  so 
  as 
  to 
  close 
  it 
  completely 
  and 
  afford 
  the 
  Scoliid 
  larva 
  the 
  necessary 
  7 
  

   interior 
  surface 
  for 
  fixing 
  its 
  silk 
  when 
  starting 
  the 
  cocoon. 
  After 
  the 
  cocoons 
  had 
  

   been 
  completed 
  they 
  were 
  stored 
  in 
  a 
  layer 
  of 
  soil 
  2 
  in. 
  deep, 
  which 
  was 
  always 
  

   kept 
  moist. 
  

  

  The 
  Life-cycle 
  of 
  Scolia 
  oryctophaga. 
  

  

  Egg. 
  — 
  The 
  egg 
  is 
  white, 
  elliptical, 
  slightly 
  arched, 
  and 
  measures 
  4 
  mm. 
  by 
  1 
  mm. 
  ; 
  

   it 
  is 
  laid 
  in 
  the 
  middle 
  of 
  the 
  ventral 
  part 
  of 
  the 
  third 
  abdominal 
  segment 
  of 
  the 
  

   beetle 
  larva 
  (Plate 
  vii, 
  fig. 
  1). 
  

  

  