﻿XIII 
  

   SOME 
  VARIATIONS 
  IN 
  LIFE 
  HISTORY. 
  

  

  Professor 
  Osborn 
  does 
  not 
  ^ive 
  us 
  the 
  periods 
  of 
  any 
  of 
  the 
  natural 
  

   enemies 
  but 
  records 
  that 
  of 
  Clie7'mes 
  pinicorticis 
  as 
  follows: 
  

  

  1878. 
  1879. 
  

  

  Apr. 
  15. 
  Pound 
  eggs 
  and 
  adult 
  females. 
  

   Apr. 
  20-24. 
  Eggs 
  hatching 
  rapidly, 
  larvffi 
  

  

  traveling. 
  

   May 
  6. 
  Larvje 
  attaching 
  themselves 
  to 
  the 
  

  

  bark. 
  ' 
  

  

  May 
  13. 
  Becoming 
  densely 
  covered 
  with 
  May 
  V.i. 
  Lice 
  well 
  developed, 
  parasites 
  at 
  

  

  woolly 
  substance. 
  ! 
  work, 
  eggs 
  unhatched. 
  

  

  May 
  16. 
  Young 
  hatching 
  and 
  traveling. 
  

   May 
  21. 
  Winged 
  males* 
  noticed 
  for 
  the 
  first 
  , 
  May 
  21. 
  Eggclusters.newly 
  hatched 
  larva?. 
  

  

  time. 
  

  

  June 
  'A. 
  Winged 
  males 
  disappeared. 
  

  

  June 
  10. 
  Lice 
  almost 
  entirely 
  disappeared; 
  

   after 
  this 
  none 
  observed 
  during 
  the 
  sum- 
  

   mer, 
  but 
  adult 
  females 
  probably 
  present 
  

   in 
  the 
  fall. 
  

  

  winged 
  males. 
  

   May 
  27. 
  Egg 
  clusters 
  and 
  living 
  females 
  

   on 
  new 
  growth 
  of 
  wood. 
  

  

  Oct. 
  9. 
  Adult 
  females 
  abundant, 
  a 
  few 
  

   eggs, 
  and 
  an 
  occasional 
  larva. 
  

  

  The 
  presence 
  of 
  the 
  eggs 
  lato 
  in 
  the 
  autumn 
  led 
  Professor 
  Osborn 
  

   to 
  think 
  at 
  first 
  that 
  the 
  Chermcs, 
  in 
  part 
  at 
  least, 
  passed 
  the 
  winter 
  

   in 
  this 
  form, 
  but 
  he 
  adds 
  that 
  no 
  eggs 
  could 
  be 
  found 
  Jan. 
  15, 
  when 
  

   the 
  apterous 
  female 
  was 
  abundant. 
  In 
  a 
  later 
  paper 
  he 
  states 
  that 
  

   he 
  has 
  seen 
  nothing 
  to 
  warrant 
  Dr. 
  Shimer's 
  opinion 
  that 
  "the 
  nor- 
  

   mal 
  winter 
  condition 
  of 
  the 
  species 
  is 
  the 
  egg, 
  and 
  that 
  these 
  are 
  on 
  

   the 
  ground." 
  My 
  own 
  observations 
  revealed 
  no 
  eggs 
  in 
  the 
  latter 
  

   part 
  of 
  March, 
  but 
  a 
  few 
  larvse 
  were 
  found. 
  Mr. 
  John 
  Marten, 
  in 
  an 
  

   unpublished 
  note 
  dated 
  Jan. 
  9, 
  says 
  he 
  made 
  a 
  careful 
  examination 
  

   of 
  the 
  insect 
  in 
  the 
  University 
  grove 
  at 
  Urbana, 
  and 
  gives 
  in 
  some 
  

   detail 
  the 
  hiding 
  places 
  of 
  the 
  apterous 
  females 
  but 
  does 
  not 
  men- 
  

   tion 
  the 
  eggs. 
  Taken 
  together, 
  these 
  observations 
  leave 
  no 
  doubt 
  

   that 
  the 
  apterous 
  female 
  is 
  the 
  winter 
  form 
  of 
  this 
  Chermes. 
  

  

  The 
  winter 
  of 
  1896 
  broke 
  up 
  earlier 
  than 
  usual, 
  and 
  this 
  fact 
  will 
  

   probably 
  explain 
  the 
  difference 
  of 
  seven 
  to 
  ten 
  days 
  between 
  the 
  

   various 
  dates 
  in 
  the 
  life 
  of 
  the 
  Chermes, 
  as 
  recorded 
  by 
  Professor 
  

   Osborn 
  in 
  1878 
  and 
  by 
  myself 
  in 
  1896. 
  The 
  intervals 
  between 
  the 
  

   successive 
  dates 
  in 
  the 
  records 
  kept 
  by 
  each 
  are 
  not 
  so 
  divergent 
  as 
  

   to 
  be 
  irreconcilable. 
  The 
  time 
  from 
  the 
  beginning 
  of 
  hatching 
  to 
  

   the 
  attachment 
  of 
  the 
  larva* 
  is 
  given 
  by 
  him 
  as 
  sixteen 
  days 
  and 
  in 
  

   my 
  record 
  as 
  eleven; 
  from 
  egg-hatching 
  to 
  appearance 
  of 
  winged 
  

   form 
  is 
  in 
  his 
  record 
  thirty-one 
  days, 
  in 
  mine 
  twenty-four; 
  but 
  to 
  

   my 
  date 
  five 
  more 
  days 
  should 
  be 
  added 
  to 
  reach 
  the 
  time 
  when 
  they 
  

   were 
  appearing 
  most 
  rapidly. 
  Professor 
  Osborn's 
  record 
  gives 
  twelve 
  

   days' 
  existence 
  for 
  the 
  winged 
  form, 
  mine 
  fourteen. 
  

  

  Professor 
  Osborn's 
  record 
  for 
  1879 
  shows 
  a 
  peculiar 
  condition 
  of 
  

   the 
  lice, 
  one 
  quite 
  at 
  variance 
  with 
  that 
  of 
  the 
  previous 
  year. 
  The 
  eggs 
  

   were 
  still 
  unhatched 
  seven 
  days 
  later 
  than 
  the 
  time 
  when 
  the 
  larva? 
  

   had 
  begun 
  attaching 
  themselves 
  to 
  the 
  bark 
  in 
  1878, 
  and 
  twenty-three 
  

   days 
  later 
  than 
  the 
  hatching 
  had 
  begun 
  in 
  that 
  year. 
  Nevertheless, 
  

  

  * 
  In 
  a 
  publication 
  issued 
  on 
  this 
  subject 
  in 
  1884 
  by 
  Professor 
  Osborn, 
  he 
  states 
  that 
  he 
  has 
  

   been 
  unable 
  to 
  distinguish 
  male 
  and 
  female 
  in 
  the 
  winged 
  form. 
  It 
  is 
  probable 
  that 
  this 
  

   form 
  consists 
  of 
  females 
  onlv. 
  

  

  