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  laid 
  by 
  the 
  latter 
  being 
  however 
  more 
  numerous 
  and 
  turning 
  brownish 
  

   after 
  3-4 
  days, 
  while 
  the 
  eggs 
  of 
  S. 
  squalidus 
  remain 
  white. 
  

  

  The 
  eggs 
  hatch 
  in 
  about 
  12 
  or 
  13 
  days, 
  and 
  the 
  larvae 
  immediately 
  

   drop 
  to 
  the 
  earth. 
  Paczoski 
  previously 
  assumed 
  that 
  the 
  larvae 
  live 
  

   in 
  the 
  earth 
  and 
  the 
  observations 
  in 
  1912 
  by 
  Nikitin 
  supported 
  this 
  ; 
  

   the 
  author's 
  investigations 
  have 
  also 
  proved 
  that 
  the 
  larvae 
  feed 
  on 
  the 
  

   roots 
  of 
  trees 
  and 
  that 
  they 
  pass 
  two 
  years 
  there 
  before 
  pupating. 
  

   Large 
  larvae 
  were 
  discovered 
  along 
  the 
  roots 
  of 
  a 
  service 
  tree 
  and 
  

   microscopical 
  examination 
  of 
  their 
  intestines 
  showed 
  the 
  presence 
  of 
  

   tissues 
  of 
  bark 
  (hber), 
  the 
  roots 
  bearing 
  clear 
  evidence 
  of 
  injury 
  ; 
  the 
  

   same 
  results 
  were 
  also 
  obtained 
  experimentally. 
  The 
  larvae 
  which 
  

   emerge 
  in 
  spring 
  do 
  not 
  finish 
  their 
  development 
  the 
  same 
  year, 
  but 
  

   pupate 
  only 
  in 
  August 
  of 
  the 
  following 
  year, 
  producing 
  beetles 
  in 
  

   September 
  which 
  winter 
  again 
  and 
  issue 
  from 
  the 
  earth 
  only 
  in 
  the 
  

   following 
  spring. 
  The 
  author 
  has 
  not 
  been 
  able 
  to 
  ascertain 
  the 
  

   number 
  of 
  moults 
  and 
  only 
  once 
  did 
  he 
  find 
  a 
  freshly 
  moulted 
  larva 
  

   with 
  the 
  old 
  skin 
  still 
  near 
  it 
  ; 
  usually 
  the 
  larvae 
  devour 
  the 
  old 
  skin. 
  

   The 
  pupa 
  lies 
  at 
  a 
  depth 
  of 
  18-25 
  inches, 
  which 
  is 
  also 
  the 
  average 
  

   depth 
  at 
  which 
  the 
  larva 
  lives. 
  It 
  is 
  assumed 
  that 
  S. 
  squalidus 
  belongs 
  

   to 
  the 
  type 
  of 
  insects 
  which 
  periodically 
  multiply 
  to 
  enormous 
  numbers, 
  

   doing 
  great 
  damage 
  in 
  these 
  years 
  and 
  afterwards 
  gradually 
  disappear- 
  

   ing 
  to 
  quite 
  negligible 
  quantities 
  ; 
  the 
  years 
  1897-1898 
  were 
  years 
  of 
  

   its 
  minimum, 
  the 
  numbers 
  increased 
  during 
  the 
  following 
  years 
  and 
  

   they 
  have 
  decreased 
  again 
  during 
  the 
  past 
  three 
  years. 
  This 
  is 
  

   attributed 
  to 
  the 
  activity 
  of 
  parasites. 
  

  

  The 
  imago, 
  larva 
  and 
  pupa 
  of 
  S. 
  squalidus, 
  owing 
  to 
  their 
  subter- 
  

   ranean 
  habit, 
  have 
  few 
  dangerous 
  enemies 
  ; 
  thus 
  only 
  the 
  eggs 
  are 
  

   exposed 
  to 
  attacks 
  of 
  various 
  parasites. 
  Chief 
  amongst 
  these 
  must 
  

   be 
  placed 
  Anaphes 
  sp., 
  of 
  the 
  family 
  Mymaridae, 
  which 
  is 
  to 
  be 
  

   described 
  by 
  Kurdjumov 
  ; 
  the 
  infection 
  of 
  the 
  eggs 
  by 
  this 
  parasite 
  

   is 
  given 
  as 
  52*4 
  per 
  cent, 
  for 
  last 
  year. 
  They 
  were 
  mostly 
  infected 
  on 
  

   the 
  day 
  on 
  which 
  they 
  were 
  laid, 
  and 
  the 
  development 
  of 
  the 
  parasite 
  

   occupied 
  10-11 
  days 
  in 
  the 
  insectarium. 
  The 
  process 
  of 
  oviposition 
  

   of 
  the 
  parasite 
  is 
  fully 
  described, 
  the 
  ovipositor 
  being 
  driven 
  through 
  

   the 
  leaf 
  with 
  which 
  the 
  eggs 
  of 
  the 
  hosts 
  are 
  covered. 
  Evidently 
  the 
  

   sticky 
  material 
  ejected 
  by 
  the 
  female 
  beetle 
  to 
  hold 
  the 
  leaf 
  in 
  

   place 
  provokes 
  the 
  desire 
  to 
  lay 
  eggs 
  in 
  the 
  parasites 
  ; 
  for 
  they 
  drove 
  

   their 
  ovipositors 
  through 
  a 
  leaf 
  from 
  which 
  all 
  the 
  eggs 
  were 
  removed, 
  

   but 
  paid 
  no 
  attention 
  to 
  eggs 
  offered 
  without 
  a 
  leaf. 
  Only 
  those 
  eggs 
  

   which 
  were 
  infested 
  early 
  in 
  their 
  development 
  produce 
  parasites 
  ; 
  

   when 
  the 
  embryo 
  of 
  the 
  host 
  has 
  already 
  developed 
  there 
  is 
  evidently 
  

   not 
  sufficient 
  nourishment 
  left 
  for 
  the 
  parasite, 
  which 
  perishes 
  with 
  

   the 
  host. 
  

  

  Two 
  species 
  of 
  Eulophus 
  act 
  as 
  ectoparasites 
  of 
  eggs 
  of 
  S. 
  squalidus. 
  

   One 
  of 
  these 
  species 
  emerges 
  from 
  the 
  pupa 
  during 
  the 
  same 
  summer, 
  

   while 
  the 
  second 
  one 
  winters 
  in 
  the 
  pupal 
  stage 
  on 
  the 
  same 
  spot 
  where 
  

   the 
  eggs 
  of 
  the 
  host 
  were 
  situated. 
  These 
  species 
  are 
  not 
  numerous 
  

   and 
  destroyed 
  only 
  about 
  9 
  '2 
  per 
  cent, 
  of 
  eggs 
  in 
  1913. 
  Each 
  larva 
  

   of 
  the 
  parasite 
  requires 
  5-6 
  eggs 
  of 
  the 
  host 
  for 
  its 
  development 
  ; 
  the 
  

   larval 
  stage 
  lasts 
  10-11 
  days; 
  the 
  pupal 
  stage 
  of 
  one 
  of 
  them 
  12-14 
  days. 
  

   The 
  eggs 
  of 
  S. 
  squalidus 
  are 
  also 
  destroyed 
  by 
  various 
  predaceous 
  insects 
  

   such 
  as 
  Aelothrips 
  fasciata, 
  Hal. 
  and 
  Haplothrips 
  aculeata 
  kurdjumovi, 
  

   Kamy, 
  subsp. 
  nov. 
  The 
  author 
  describes 
  the 
  larva 
  of 
  the 
  latter 
  

  

  