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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1922. 
  

  

  their 
  restless 
  comrade 
  has 
  but 
  a 
  common 
  caterpillar 
  affliction 
  and 
  

   must 
  be 
  endured. 
  

  

  Many 
  of 
  these 
  little 
  traits 
  make 
  the 
  caterpillars 
  seem 
  almost 
  hu- 
  

   man. 
  But, 
  of 
  course, 
  this 
  is 
  just 
  a 
  popular 
  form 
  of 
  expression. 
  In 
  

   fact, 
  it 
  is 
  too 
  popular 
  — 
  we 
  take 
  too 
  much 
  satisfaction 
  in 
  referring 
  

   to 
  our 
  faults 
  as 
  particularly 
  human 
  characteristics. 
  What 
  we 
  really 
  

   should 
  say 
  is 
  not 
  how 
  much 
  tent 
  caterpillars 
  are 
  like 
  us 
  in 
  their 
  

   shortcomings, 
  but 
  how 
  much 
  we 
  are 
  still 
  like 
  tent 
  caterpillars. 
  We 
  

   both 
  revert 
  more 
  or 
  less 
  in 
  our 
  instincts 
  to 
  times 
  before 
  we 
  lived 
  in 
  

   communities, 
  to 
  times 
  when 
  our 
  ancestors 
  lived 
  as 
  individuals 
  irre- 
  

   sponsible 
  one 
  to 
  another. 
  

  

  The 
  tent 
  caterpillars 
  ordinarily 
  shed 
  their 
  skins 
  six 
  times 
  during 
  

   their 
  lives. 
  At 
  each 
  molt 
  the 
  skin 
  splits 
  along 
  the 
  middle 
  of 
  the 
  

   back 
  on 
  the 
  first 
  three 
  body 
  segments 
  and 
  around 
  the 
  back 
  of 
  the 
  

   head. 
  It 
  is 
  then 
  pushed 
  off 
  over 
  the 
  rear 
  end 
  of 
  the 
  body, 
  usually 
  in 
  

   one 
  piece, 
  though 
  most 
  other 
  caterpillars 
  cast 
  off 
  the 
  head 
  covering 
  

   separate 
  from 
  the 
  skin 
  of 
  the 
  body 
  in 
  all 
  molts 
  but 
  the 
  last. 
  The 
  

   molting 
  takes 
  place 
  in 
  the 
  tent 
  and 
  renders 
  the 
  caterpillars 
  inactive 
  

   for 
  the 
  greater 
  part 
  of 
  two 
  days. 
  When 
  most 
  of 
  them 
  molt 
  at 
  the 
  

   same 
  time 
  there 
  results 
  an 
  abrupt 
  cessation 
  of 
  activity 
  in 
  the 
  colony. 
  

   By 
  the 
  time 
  the 
  caterpillars 
  reach 
  maturity 
  the 
  discarded 
  skins 
  in 
  

   a 
  tent 
  outnumber 
  the 
  caterpillars 
  5 
  to 
  1. 
  

  

  The 
  first 
  stage 
  of 
  the 
  caterpillars, 
  as 
  already 
  described 
  (fig. 
  2, 
  D), 
  

   suggests 
  nothing 
  of 
  the 
  color 
  pattern 
  of 
  the 
  later 
  stages, 
  but 
  in 
  

   Stage 
  II 
  the 
  spots 
  and 
  stripes 
  of 
  the 
  mature 
  caterpillars 
  begin 
  to 
  

   be 
  formed. 
  In 
  succeeding 
  stages 
  the 
  characters 
  become 
  more 
  and 
  

   more 
  like 
  those 
  of 
  the 
  sixth 
  or 
  last 
  stage 
  (fig. 
  6), 
  when 
  the 
  colors 
  

   are 
  most 
  intensified 
  and 
  their 
  pattern 
  best 
  defined. 
  Particularly 
  

   striking 
  now 
  are 
  the 
  velvety 
  black 
  head 
  with 
  the 
  gray 
  collar 
  behind, 
  

   the 
  black 
  shield 
  of 
  the 
  first 
  segment 
  split 
  with 
  a 
  median 
  zone 
  of 
  

   brown, 
  the 
  white 
  stripe 
  clown 
  the 
  middle 
  of 
  of 
  the 
  back, 
  the 
  large 
  

   black 
  lateral 
  blotches, 
  each 
  inclosing 
  a 
  spot 
  of 
  silvery 
  bluish 
  white, 
  

   the 
  distinctly 
  bluish 
  color 
  between 
  and 
  below 
  the 
  blotches, 
  and 
  the 
  

   hump 
  on 
  the 
  eleventh 
  segment, 
  where 
  the 
  median 
  white 
  line 
  is 
  almost 
  

   obliterated 
  by 
  the 
  crowding 
  of 
  the 
  black 
  from 
  the 
  sides. 
  Yet 
  the 
  

   creatures 
  wearing 
  all 
  this 
  lavishness 
  of 
  decoration 
  make 
  no 
  ostenta- 
  

   tious 
  show, 
  for 
  the 
  colors 
  are 
  all 
  nicely 
  subdued 
  beneath 
  the 
  long 
  red- 
  

   dish 
  brown 
  hairs 
  that 
  clothe 
  the 
  body. 
  

  

  In 
  the 
  last 
  stage 
  the 
  average 
  full-grown 
  caterpillar 
  is 
  about 
  2 
  

   inches 
  long, 
  but 
  some 
  reach 
  a 
  length 
  of 
  2J 
  inches 
  when 
  fully 
  

   stretched 
  out. 
  The 
  head 
  measures 
  3 
  to 
  3£ 
  millimeters 
  wide 
  in 
  this 
  

   stage, 
  or 
  a 
  little 
  more 
  than 
  one-eighth 
  inch. 
  In 
  Stage 
  V 
  the 
  largest 
  

   heads 
  are 
  not 
  wider 
  than 
  2$ 
  millimeters; 
  in 
  Stage 
  IV 
  they 
  do 
  not 
  

   exceed 
  H 
  millimeters 
  ; 
  in 
  III, 
  1 
  millimeter 
  ; 
  in 
  II, 
  about 
  two-thirds 
  

  

  