﻿INTRODUCING 
  SCOLIID 
  WASPS 
  FROM 
  MADAGASCAR 
  TO 
  MAURITIUS. 
  247 
  

  

  and 
  its 
  surroundings 
  on 
  the 
  succeeding 
  days, 
  we 
  satisfied 
  ourselves 
  that 
  we 
  had 
  

   captured 
  all 
  the 
  Scoliids 
  attracted 
  by 
  the 
  eucalyptus 
  flowers 
  on 
  which 
  we 
  had 
  detected 
  

   them. 
  The 
  question 
  presented 
  itself 
  to 
  our 
  minds, 
  whether 
  the 
  absence 
  of 
  these 
  

   Scoliids 
  from 
  all 
  the 
  localities 
  hitherto 
  visited 
  could 
  be 
  attributed 
  to 
  the 
  fact 
  that 
  

   the 
  season 
  was 
  not 
  the 
  one 
  during 
  which 
  the 
  insect 
  exists 
  in 
  the 
  adult 
  stage, 
  or 
  

   whether 
  it 
  was 
  to 
  be 
  ascribed 
  to 
  the 
  absence 
  from 
  those 
  localities 
  of 
  these 
  special 
  

   flowers, 
  which 
  these 
  insects 
  visit 
  by 
  preference. 
  

  

  To 
  explain 
  their 
  sudden 
  appearance 
  in 
  limited 
  numbers 
  in 
  this 
  village 
  it 
  was 
  

   reasonable 
  to 
  suppose 
  them 
  to 
  have 
  sedentary 
  habits 
  tending 
  to 
  keep 
  them 
  clustered 
  

   within 
  a 
  limited 
  area, 
  as 
  well 
  as 
  an 
  extraordinary 
  capacity 
  of 
  flight 
  enabling 
  them 
  to 
  

   seek 
  for 
  their 
  favourite 
  flowers 
  at 
  long 
  distances, 
  and 
  in 
  this 
  way 
  to 
  be 
  present 
  in 
  

   numbers 
  wherever 
  these 
  flowers 
  are 
  to 
  be 
  found. 
  These 
  hypotheses 
  were 
  quite 
  

   reasonable, 
  but 
  as 
  we 
  were 
  not 
  in 
  a 
  position 
  to 
  verify 
  them 
  without 
  losing 
  the 
  

   opportunity 
  of 
  proceeding 
  to 
  Ste 
  Marie, 
  where 
  we 
  hoped 
  to 
  work 
  under 
  more 
  favourable 
  

   conditions, 
  we 
  decided 
  to 
  undertake 
  the 
  journey. 
  

  

  We 
  landed 
  at 
  Ste 
  Marie 
  in 
  the 
  afternoon 
  of 
  4th 
  July, 
  after 
  having 
  experienced 
  

   the 
  greatest 
  difficulties 
  in 
  the 
  transport 
  of 
  our 
  breeding-cages, 
  which, 
  both 
  in 
  respect 
  

   of 
  their 
  weight 
  and 
  volume, 
  were 
  exactly 
  what 
  they 
  ought 
  not 
  to 
  have 
  been. 
  

  

  From 
  the 
  5th 
  to 
  the 
  9th 
  July 
  we 
  visited 
  the 
  south 
  and 
  south-eastern 
  parts 
  of 
  the 
  

   island, 
  without 
  any 
  result 
  ; 
  while 
  the 
  natives 
  we 
  employed 
  to 
  search 
  for 
  Orycles 
  

   larvae 
  and 
  adult 
  Scoliids 
  were 
  no 
  more 
  successful, 
  although 
  flowers 
  capable 
  of 
  

   attracting 
  the 
  wasps 
  were 
  plentiful. 
  The 
  coconut 
  palms, 
  which 
  very 
  rarely 
  exceeded 
  

   30 
  plants 
  per 
  village, 
  did 
  not 
  show 
  any 
  signs 
  of 
  damage 
  due 
  to 
  Oryctes. 
  Decaying 
  

   trunks 
  were 
  therefore 
  extremely 
  rare, 
  and 
  the 
  only 
  larvae 
  of 
  0. 
  simiar 
  obtained 
  were 
  

   found 
  in 
  a 
  decaying 
  stump 
  of 
  Bois 
  Noir 
  (Albizzia 
  lebbek). 
  So 
  far 
  as 
  Scoliids 
  were 
  

   concerned, 
  only 
  Elis 
  thoracica 
  was 
  observed 
  in 
  numbers 
  on 
  Stachytarpheta 
  indica. 
  

  

  On 
  the 
  whole 
  the 
  result 
  of 
  our 
  stay 
  in 
  Ste 
  Marie 
  — 
  where, 
  according 
  to 
  Coquerel, 
  

   we 
  ought 
  to 
  have 
  found 
  the 
  insects 
  we 
  came 
  for 
  in 
  abundance 
  — 
  proved 
  unsatisfactory 
  

   so 
  far 
  as 
  the 
  principal 
  object 
  was 
  concerned 
  ; 
  on 
  the 
  other 
  hand, 
  it 
  was 
  not 
  entirely 
  

   devoid 
  of 
  interest, 
  considering 
  the 
  deductions 
  following 
  from 
  the 
  data 
  gathered. 
  

  

  That 
  S. 
  oryctophaga, 
  as 
  stated 
  by 
  Coquerel, 
  was 
  a 
  serious 
  enemy 
  of 
  0. 
  simiar 
  

   and 
  0. 
  ranavalo 
  was 
  shown 
  by 
  the 
  relative 
  scarcity 
  of 
  these 
  two 
  beetles. 
  No 
  doubt 
  

   the 
  disappearance 
  of 
  the 
  coconut 
  plantations, 
  which 
  through 
  their 
  state 
  of 
  neglect 
  

   favoured 
  the 
  development 
  of 
  Oryctes, 
  had 
  greatly 
  contributed 
  to 
  reduce 
  their 
  numbers 
  ; 
  

   on 
  the 
  other 
  hand, 
  there 
  existed 
  numerous 
  habitats 
  scattered 
  along 
  the 
  west 
  coast 
  

   where 
  these 
  insects 
  would 
  certainly 
  have 
  been 
  much 
  more 
  numerous 
  had 
  they 
  not 
  

   been 
  controlled 
  to 
  an 
  appreciable 
  extent 
  by 
  their 
  natural 
  enemies. 
  This 
  was 
  

   particularly 
  striking 
  on 
  Mr. 
  Leroy's 
  plantation, 
  where 
  Oryctes 
  larvae 
  were 
  relatively 
  

   scarce 
  in 
  spite 
  of 
  the 
  abundance 
  of 
  decaying 
  coconut 
  trunks. 
  

  

  We 
  had, 
  moreover, 
  verified 
  one 
  of 
  the 
  hypotheses 
  put 
  forward 
  at 
  the 
  beginning 
  

   of 
  this 
  report 
  to 
  explain 
  the 
  sudden 
  appearance 
  of 
  Scoliids 
  in 
  Tanamakoa, 
  viz., 
  that 
  

   the 
  Scoliids 
  could 
  be 
  attracted 
  from 
  far 
  by 
  special 
  plants 
  for 
  which 
  they 
  exhibited 
  

   a 
  marked 
  partiality. 
  Elis 
  thoracica, 
  for 
  example, 
  which 
  we 
  found 
  in 
  considerable 
  

   numbers 
  on 
  " 
  queue 
  de 
  rat 
  " 
  {Stachytarpheta 
  indica) 
  on 
  the 
  plain 
  of 
  Tanamakoa, 
  was 
  

   again 
  found 
  at 
  Ste 
  Marie 
  visiting 
  the 
  same 
  plant 
  exclusively. 
  Again, 
  5. 
  oryctophaga, 
  

   which, 
  it 
  is 
  true, 
  occurred 
  in 
  very 
  small 
  numbers, 
  was 
  never 
  found 
  visiting 
  any 
  other 
  

   plant 
  except 
  a 
  certain 
  shrub 
  with 
  red 
  berries, 
  the 
  same 
  being 
  true 
  for 
  5. 
  iridicolor. 
  

  

  There 
  were 
  on 
  the 
  plain 
  contiguous 
  to 
  the 
  coconut 
  plantation, 
  and 
  on 
  the 
  

   plantation 
  itself, 
  various 
  other 
  flowers 
  such 
  as 
  Convolvulus, 
  Lantana, 
  Stachytarpheta, 
  

   a 
  wild 
  variety 
  of 
  periwinkle, 
  and 
  many 
  others 
  which 
  we 
  could 
  not 
  identify, 
  of 
  which 
  

   the 
  insects 
  took 
  no 
  heed. 
  The 
  preference 
  shown 
  by 
  these 
  Scoliids 
  for 
  the 
  shrub 
  

   with 
  red 
  berries 
  was 
  so 
  marked 
  that 
  it 
  soon 
  caught 
  our 
  attention, 
  and 
  subsequently 
  

   we 
  searched 
  for 
  them 
  only 
  on 
  these 
  plants, 
  which, 
  though 
  covered 
  with 
  fruits, 
  had 
  

   still 
  a 
  few 
  flowers. 
  All 
  our 
  captures 
  were 
  effected 
  on 
  some 
  10 
  shrubs, 
  and 
  the 
  plant 
  

  

  (8053) 
  r2 
  

  

  