﻿106 
  F. 
  \V. 
  DRY. 
  

  

  The 
  first 
  plantation 
  is 
  the 
  largest 
  and 
  the 
  records 
  cover 
  the 
  longest 
  time. 
  We 
  may 
  

   be 
  sure 
  that 
  an 
  appreciable 
  proportion 
  of 
  the 
  beetles 
  present 
  in 
  the 
  plantation 
  were 
  

   captured. 
  The 
  labour 
  is 
  well 
  managed 
  on 
  the 
  plantation, 
  and 
  with 
  trees 
  like 
  the 
  

   coconut 
  palm, 
  which 
  is 
  usually 
  planted 
  on 
  this 
  estate 
  at 
  the 
  rate 
  of 
  55 
  to 
  the 
  acre, 
  

   every 
  one 
  can 
  be 
  examined. 
  The 
  boys 
  readily 
  recognise 
  trees 
  that 
  have 
  been 
  attacked 
  

   bv 
  the 
  chewed 
  material 
  thrown 
  out 
  by 
  the 
  beetle 
  and 
  then 
  look 
  to 
  see 
  if 
  the 
  insect 
  

   is 
  still 
  there. 
  A 
  good 
  search, 
  therefore, 
  was 
  made, 
  and 
  while 
  other 
  unknown 
  factors 
  

   may 
  have 
  helped 
  to 
  bring 
  about 
  the 
  result, 
  in 
  the 
  last 
  of 
  the 
  three 
  years 
  the 
  beetles 
  

   were 
  greatly 
  reduced 
  in 
  numbers. 
  It 
  may 
  thus 
  safely 
  be 
  concluded 
  that 
  we 
  are 
  

   concerned 
  with 
  tens 
  of 
  beetles 
  to 
  the 
  acre 
  a 
  year 
  rather 
  than 
  with 
  hundreds 
  or 
  thousands. 
  

   Besides, 
  the 
  effects 
  of 
  attack 
  by 
  a 
  single 
  individual 
  are 
  quite 
  perceptible, 
  and 
  it 
  has 
  

   already 
  been 
  mentioned 
  that 
  in 
  confinement 
  the 
  beetles 
  live 
  a 
  long 
  time. 
  With 
  

   this 
  species, 
  therefore, 
  every 
  individual 
  adult 
  counts. 
  

  

  With 
  the 
  smallness 
  of 
  the 
  number 
  of 
  adult 
  individuals 
  one 
  at 
  once 
  correlates 
  the 
  

   fact 
  that 
  beetle 
  grubs 
  were 
  much 
  easier 
  to 
  obtain, 
  as 
  they 
  were 
  all 
  the 
  time 
  that 
  

   I 
  was 
  at 
  the 
  Coast. 
  All 
  the 
  stages 
  of 
  the 
  beetle 
  were 
  to 
  be 
  found 
  at 
  an} 
  7 
  time. 
  

   I 
  have 
  no 
  record 
  of 
  the 
  relative 
  numbers 
  of 
  beetles 
  and 
  grubs 
  captured 
  in 
  a 
  given 
  area 
  

   in 
  a 
  given 
  time, 
  but 
  if 
  a 
  large 
  number 
  of 
  grubs 
  were 
  wanted, 
  two 
  boys 
  chopping 
  up 
  

   logs 
  at 
  Changamwe 
  would 
  collect 
  a 
  couple 
  of 
  hundred 
  or 
  more 
  in 
  a 
  day, 
  while 
  at 
  the 
  

   same 
  time 
  it 
  was 
  economical 
  to 
  pav 
  the 
  natives 
  at 
  the 
  same 
  place 
  about 
  a 
  penny 
  

   for 
  each 
  beetle 
  they 
  brought 
  in. 
  In 
  collecting 
  the 
  grubs 
  dead 
  ones 
  were 
  very 
  often 
  

   found, 
  and 
  the 
  high 
  mortality 
  amongst 
  the 
  grubs 
  is 
  at 
  any 
  rate 
  suggestive. 
  A 
  similar 
  

   high 
  mortality 
  in 
  the 
  early 
  stages 
  has 
  been 
  found 
  in 
  other 
  boring 
  insects. 
  For 
  

   example, 
  Dr. 
  Van 
  Someren, 
  the 
  Government 
  Dentist 
  at 
  Nairobi, 
  told 
  me 
  that 
  he 
  had 
  

   found 
  this 
  to 
  be 
  so 
  with 
  the 
  carpenter 
  bee, 
  Xylocopa 
  flavorufa, 
  de 
  G., 
  and 
  Dr. 
  E. 
  

   Schwarz, 
  in 
  conversation 
  at 
  Washington 
  recently, 
  said 
  that 
  it 
  is 
  frequently 
  so 
  with 
  

   boring 
  beetles. 
  While 
  the 
  limiting 
  factors 
  of 
  the 
  beetle 
  remain 
  to 
  be 
  investigated, 
  

   it 
  does 
  look 
  probable 
  that 
  mortality 
  through 
  overcrowding 
  in 
  the 
  breeding-places 
  

   is 
  a 
  factor 
  that 
  actuallv 
  exercises 
  what 
  Howard 
  calls 
  "facultative 
  control." 
  

  

  A 
  Comparison 
  of 
  the 
  Extent 
  of 
  Beetle 
  Damage 
  in 
  two 
  Coconut 
  Areas 
  where 
  Conditions 
  

   affecting 
  the 
  Beetle 
  were 
  different. 
  

  

  A 
  rough 
  index 
  of 
  the 
  extent 
  of 
  beetle 
  damage 
  in 
  an 
  area 
  was 
  obtained 
  in 
  a 
  simple 
  

   way. 
  In 
  boring 
  holes 
  into 
  the 
  " 
  cabbage 
  " 
  at 
  the 
  top 
  of 
  the 
  coconut 
  tree 
  the 
  beetles 
  

   in 
  the 
  great 
  majority 
  of 
  cases 
  cut 
  across 
  the 
  pinnae 
  of 
  one 
  or 
  more 
  leaves 
  while 
  they 
  

   are 
  still 
  folded 
  in 
  the 
  heart 
  of 
  the 
  plant. 
  Occasionally 
  signs 
  of 
  attack 
  can 
  be 
  seen 
  

   on 
  the 
  stalks 
  of 
  the 
  leaves 
  without 
  the 
  pinnae 
  being 
  affected. 
  When 
  leaves 
  with 
  

   damaged 
  pinnae 
  unfold, 
  and 
  so 
  long 
  as 
  they 
  remain 
  on 
  the 
  plant, 
  they 
  look 
  as 
  if 
  

   portions 
  have 
  been 
  neatly 
  taken 
  out 
  by 
  a 
  person 
  beginning 
  to 
  cut 
  at 
  some 
  point 
  on 
  

   the 
  edge 
  and 
  cutting 
  in 
  a 
  straight 
  line 
  across 
  the 
  pinnae 
  more 
  or 
  less 
  at 
  right 
  angles 
  

   to 
  the 
  stalk. 
  All 
  the 
  pinnae 
  as 
  far 
  as 
  the 
  stalk 
  may 
  be 
  affected, 
  or 
  the 
  attack 
  may 
  

   stop 
  short 
  of 
  the 
  stalk. 
  Sometimes 
  the 
  pinnae 
  on 
  both 
  sides 
  of 
  the 
  stalk 
  have 
  been 
  

   cut 
  quite 
  symmetrically. 
  While 
  weaver-birds 
  sometimes 
  produce 
  a 
  rather 
  similar 
  

   effect 
  and 
  the 
  wind 
  may 
  sometimes 
  injure 
  the 
  leaves, 
  one 
  can 
  tell 
  very 
  fairly 
  which 
  

   leaves 
  have 
  been 
  attacked. 
  Counts 
  of 
  such 
  leaves 
  have 
  therefore 
  been 
  used 
  to 
  get 
  

   a 
  rough 
  index 
  of 
  the 
  extent 
  of 
  beetle 
  damage 
  in 
  a 
  coconut 
  area. 
  The 
  two 
  areas 
  to 
  

   which 
  this 
  method 
  was 
  applied 
  are 
  strikingly 
  different 
  as 
  regards 
  conditions 
  affecting 
  

   the 
  coconut 
  beetle. 
  

  

  The 
  first 
  area 
  is 
  the 
  mainland 
  near 
  Mombasa 
  in 
  the 
  coconut 
  area 
  in 
  non-European 
  

   hands. 
  A 
  large 
  number 
  of 
  holdings, 
  mostly 
  small, 
  adjoin 
  to 
  make 
  hundreds 
  of 
  acres 
  of 
  

   cultivated 
  land 
  where 
  coconuts 
  are 
  mixed 
  with 
  other 
  plants. 
  The 
  coconuts 
  have 
  

   mostly 
  been 
  planted 
  in 
  a 
  haphazard 
  way, 
  and 
  old 
  and 
  young 
  trees 
  are 
  growing 
  side 
  

   by 
  side. 
  The 
  grass 
  is 
  often 
  long, 
  but 
  there 
  is 
  little 
  bush. 
  There 
  are 
  quite 
  a 
  number 
  

  

  