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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1922. 
  

  

  The 
  web-spinning 
  habit 
  is 
  one 
  which, 
  as 
  we 
  shall 
  see, 
  these 
  cater- 
  

   pillars 
  will 
  develop 
  to 
  a 
  much 
  greater 
  extent 
  later 
  in 
  their 
  lives, 
  

   for 
  our 
  little 
  acquaintances 
  are 
  young 
  tent 
  caterpillars. 
  They 
  are 
  

   found 
  most 
  often, 
  amongst 
  woodland 
  trees, 
  on 
  the 
  choke 
  cherry 
  and 
  

   wild 
  black 
  cherry. 
  But 
  they 
  frequently 
  infest 
  apple 
  trees 
  in 
  the 
  

   orchards, 
  and 
  for 
  this 
  reason 
  their 
  species 
  has 
  been 
  named 
  the 
  

   Apple-tree 
  Tent 
  Caterpillar, 
  to 
  distinguish 
  it 
  from 
  related 
  forms 
  

   that 
  do 
  not 
  commonly 
  inhabit 
  cultivated 
  fruit 
  trees. 
  The 
  scientific 
  

   name 
  is 
  Malacosoma 
  aniericana. 
  

  

  The 
  egg 
  masses 
  are 
  not 
  hard 
  to 
  find 
  at 
  this 
  season. 
  They 
  are 
  gen- 
  

   erally 
  placed 
  near 
  the 
  tips 
  of 
  the 
  twigs, 
  which 
  they 
  appear 
  to 
  sur- 
  

   round, 
  and 
  being 
  of 
  the 
  same 
  brownish 
  color 
  as 
  the 
  bark 
  they 
  look 
  

   like 
  swollen 
  parts 
  of 
  the 
  twigs 
  themselves 
  (fig. 
  2, 
  A). 
  Most 
  of 
  them 
  

   are 
  five-eighths 
  to 
  seven-eighths 
  of 
  an 
  inch 
  in 
  length 
  and 
  almost 
  

   half 
  of 
  this 
  in 
  width, 
  but 
  they 
  vary 
  in 
  thickness 
  with 
  the 
  diameter 
  

   of 
  the 
  twig. 
  A 
  closer 
  inspection 
  shows 
  that 
  the 
  mass 
  really 
  clasps 
  

   the 
  twig, 
  or 
  incloses 
  it 
  like 
  a 
  thick 
  jacket 
  lapped 
  clear 
  around. 
  In 
  

   form 
  the 
  masses 
  are 
  usually 
  symmetrical, 
  tapering 
  at 
  each 
  end, 
  but 
  

   some 
  are 
  of 
  irregular 
  shapes, 
  and 
  those 
  that 
  have 
  been 
  placed 
  at 
  a 
  

   forking 
  or 
  against 
  a 
  bud 
  have 
  one 
  end 
  enlarged. 
  

  

  The 
  greater 
  part 
  of 
  an 
  egg 
  mass 
  consists 
  of 
  the 
  covering 
  material, 
  

   which 
  is 
  a 
  brittle, 
  filmy 
  substance 
  like 
  dry 
  mucilage. 
  Some 
  of 
  it 
  is 
  

   often 
  broken 
  away, 
  and 
  sometimes 
  the 
  tops 
  of 
  the 
  eggs 
  are 
  entirely 
  

   bare. 
  The 
  eggs 
  are 
  placed 
  in 
  a 
  single 
  layer 
  next 
  the 
  bark 
  (fig. 
  2, 
  B) 
  , 
  

   and 
  there 
  are 
  usually 
  300 
  or 
  400 
  of 
  them. 
  They 
  look 
  like 
  little, 
  pale 
  

   gray 
  porcelain 
  jars 
  packed 
  closely 
  together 
  and 
  glued 
  to 
  the 
  twig 
  by 
  

   their 
  rounded 
  and 
  somewhat 
  compressed 
  lower 
  ends. 
  The 
  tops 
  are 
  

   flat 
  or 
  a 
  little 
  convex. 
  Each 
  is 
  the 
  twenty-fourth 
  of 
  an 
  inch 
  in 
  

   height, 
  about 
  two 
  thirds 
  of 
  this 
  in 
  width, 
  and 
  has 
  a 
  capacity 
  of 
  one 
  

   caterpillar. 
  The 
  covering 
  is 
  usually 
  half 
  again 
  as 
  deep 
  as 
  the 
  height 
  

   of 
  the 
  eggs, 
  but 
  varies 
  in 
  thickness 
  in. 
  different 
  specimens. 
  The 
  outer 
  

   surface 
  is 
  smooth 
  and 
  polished, 
  but 
  the 
  interior 
  is 
  full 
  of 
  irregular, 
  

   many-sided 
  air 
  spaces, 
  separated 
  from 
  one 
  another 
  by 
  thin, 
  filmy 
  

   partitions 
  (fig. 
  2, 
  B). 
  

  

  Wherever 
  the 
  covering 
  has 
  been 
  broken 
  away, 
  the 
  bases 
  of 
  the 
  

   partition 
  walls 
  leave 
  brown 
  lines 
  that 
  look 
  like 
  cords 
  strapped 
  and 
  

   tied 
  into 
  an 
  irregular 
  net 
  over 
  the 
  eggs 
  (B), 
  as 
  if 
  for 
  double 
  security 
  

   against 
  insurrection 
  on 
  the 
  part 
  of 
  the 
  inmates. 
  But 
  neither 
  shells 
  

   nor 
  fastenings 
  will 
  offer 
  effective 
  resistance 
  to 
  the 
  little 
  thieves 
  when 
  

   they 
  are 
  taken 
  with 
  the 
  urge 
  for 
  freedom. 
  Each 
  is 
  provided 
  with 
  

   efficient 
  cutting 
  instruments 
  in 
  the 
  form 
  of 
  sharp-toothed 
  jaws 
  that 
  

   will 
  enable 
  it 
  to 
  open 
  a 
  round 
  hole 
  through 
  the 
  roof 
  of 
  its 
  cell 
  (fig. 
  

   2, 
  C). 
  The 
  superstructure 
  is 
  then 
  easily 
  penetrated, 
  and 
  the 
  emerg- 
  

   ing 
  caterpillar 
  finds 
  itself 
  on 
  the 
  surface 
  of 
  its 
  former 
  prison, 
  along 
  

   with 
  its 
  several 
  hundred 
  brothers 
  and 
  sisters, 
  when 
  all 
  are 
  out. 
  

  

  