﻿XX 
  

  

  summer. 
  It 
  will 
  be 
  observed 
  that 
  six 
  different 
  forms 
  are 
  recognized 
  

   as 
  constituting 
  the 
  cycle, 
  the 
  fiindatrix 
  and 
  sexual.es 
  being 
  found 
  

   upon 
  the 
  fir 
  alone, 
  the 
  emitjrantes 
  and 
  exides 
  upon 
  the 
  pine 
  alone, 
  

   the 
  migrantes 
  alatw 
  and 
  sexii/parce, 
  winged 
  forms, 
  upon 
  both. 
  It 
  is 
  

   a 
  remarkable 
  history. 
  

  

  Finally, 
  reference 
  is 
  made 
  to 
  the 
  forms 
  of 
  Cheriues 
  found 
  on 
  the 
  

   white 
  pine, 
  in 
  a 
  short 
  statement 
  to 
  the 
  effect 
  that 
  they 
  are 
  not 
  wholly 
  

   unknown. 
  If 
  Chermes 
  piiiicorticis 
  should 
  be 
  found 
  to 
  have 
  another 
  

   host 
  i3lant. 
  as 
  all 
  indications 
  lead 
  us 
  to 
  suspect, 
  there 
  will, 
  I 
  think, 
  

   be 
  discovered 
  some 
  variations 
  from 
  the 
  above 
  generalized 
  history 
  as 
  

   given 
  by 
  Cholodkovsky. 
  The 
  above 
  forms 
  given 
  by 
  him 
  as 
  infesting 
  

   the 
  pines 
  do 
  not 
  agree 
  with 
  those 
  of 
  C. 
  pinicoriicis. 
  All 
  the 
  Amer- 
  

   ican 
  observers 
  who 
  have 
  specifically 
  mentioned 
  the 
  matter, 
  state 
  

   that 
  the 
  lice 
  are 
  absent 
  during 
  the 
  summer, 
  or 
  were 
  not 
  observed 
  

   during 
  the 
  summer. 
  Professor 
  Osborn 
  states 
  that 
  he 
  believes 
  the 
  

   eggs 
  to 
  be 
  depositctl 
  throughout 
  the 
  entire 
  season, 
  but 
  says 
  that 
  he 
  

   observed 
  them 
  no 
  later 
  than 
  May 
  27, 
  in 
  1879, 
  and 
  again 
  in 
  the 
  

   fall, 
  October 
  \), 
  thus 
  leaving 
  the 
  interval 
  between 
  May 
  27 
  and 
  Oc- 
  

   tober 
  9 
  unaccounted 
  for. 
  In 
  1878, 
  June 
  10, 
  he 
  notes 
  that 
  the 
  

   lice 
  had 
  almost 
  entirely 
  disappeared. 
  These 
  observations 
  seem 
  to 
  

   exclude 
  the 
  ^'exules''' 
  from 
  the 
  forms 
  of 
  C. 
  'pinicorticis 
  found 
  upon 
  

   the 
  pine. 
  If 
  this 
  form 
  exists 
  in 
  this 
  species 
  it 
  must 
  therefore 
  be 
  

   looked 
  for 
  upon 
  the 
  other 
  host 
  plant. 
  In 
  addition 
  to 
  this 
  fact, 
  C. 
  

   'pinicorticis 
  presents 
  a 
  further 
  difference 
  from 
  Cholodkovsky's 
  state- 
  

   ment 
  of 
  the 
  typical 
  life 
  history 
  in 
  that 
  there 
  is 
  no 
  winged 
  form 
  

   ("migrantes 
  (data;'") 
  which 
  lays 
  its 
  eggs 
  upon 
  the 
  pine 
  in 
  early 
  

   spring. 
  From 
  the 
  information 
  at 
  present 
  in 
  view 
  it 
  seems 
  that 
  the 
  

   pine 
  is 
  the 
  present 
  host 
  plant 
  of 
  our 
  species, 
  and 
  some 
  other 
  species 
  

   of 
  conifer 
  the 
  intermediate 
  one, 
  if 
  we 
  accept 
  the 
  idea 
  of 
  a 
  two-year 
  

   cycle. 
  On 
  the 
  other 
  hand, 
  I 
  am 
  aware 
  of 
  no 
  evidence 
  other 
  than 
  

   analogy 
  which 
  supports 
  the 
  idea 
  of 
  a 
  two-year 
  cycle 
  for 
  C. 
  jyinicor- 
  

   ticis. 
  It 
  is 
  quite 
  possible 
  that 
  the 
  cycle 
  is 
  comi3leted 
  in 
  one 
  year. 
  

   The 
  absence 
  of 
  other 
  evidence 
  than 
  analogy 
  opens 
  an 
  inviting 
  field 
  

   for 
  further 
  observation. 
  

  

  