﻿SILK 
  PRODUCED 
  BY 
  FIRST-STAGE 
  GIPSY-MOTH 
  LARVJE. 
  23 
  

  

  during 
  sudden 
  squalls 
  or 
  sharp 
  whirlwinds, 
  provided 
  the 
  tempera- 
  

   ture 
  is 
  high 
  enough 
  to 
  cause 
  the 
  caterpillars 
  to 
  become 
  active. 
  Early 
  

   in 
  the 
  spring 
  it 
  is 
  quite 
  common 
  to 
  see 
  papers 
  or 
  leaves 
  caught 
  up 
  

   by 
  such 
  winds 
  and 
  carried 
  several 
  hundred 
  feet 
  in 
  the 
  air. 
  This 
  

   often 
  results 
  in 
  these 
  objects 
  coming 
  in 
  contact 
  with 
  strong 
  currents 
  

   high 
  above 
  the 
  earth 
  and 
  being 
  carried 
  many 
  miles 
  before 
  falling. 
  

   Undoubtedly 
  the 
  same 
  thing 
  happens 
  when 
  caterpillars 
  are 
  sus- 
  

   pended 
  from 
  the 
  trees 
  by 
  the 
  silk 
  which 
  they 
  spin, 
  although 
  abso- 
  

   lute 
  proof 
  of 
  this 
  point 
  is 
  very 
  difficult 
  to 
  secure. 
  Several 
  other 
  ele- 
  

   ments 
  have 
  an 
  important 
  bearing 
  on 
  this 
  matter, 
  such 
  as 
  the 
  density 
  

   of 
  infestation 
  and 
  the 
  quantity 
  of 
  silk 
  which 
  is 
  produced 
  by 
  the 
  first- 
  

   stage 
  larva 
  1 
  . 
  

  

  QUANTITY 
  OF 
  SILK 
  PRODUCED 
  BY 
  FIRST-STAGE 
  GIPSY-MOTH 
  

  

  A 
  record 
  is 
  given 
  on 
  page 
  331 
  of 
  the 
  report 
  on 
  the 
  gipsy 
  moth, 
  

   by 
  Messrs. 
  Forbush 
  and 
  Fernald, 
  of 
  the 
  quantity 
  of 
  silk 
  produced 
  by 
  

   first 
  -stage 
  gipsy-moth 
  larvae. 
  The 
  data 
  were 
  secured 
  by 
  inducing 
  the 
  

   larva? 
  to 
  commence 
  spinning, 
  after 
  which 
  the 
  end 
  of 
  the 
  thread 
  was 
  

   attached 
  to 
  a 
  reel, 
  and 
  the 
  quantity 
  produced 
  was 
  determined 
  by 
  

   multiplying 
  the 
  circumference 
  by 
  the 
  number 
  of 
  revolutions 
  which 
  

   it 
  was 
  turned. 
  Tn 
  these 
  experiments 
  newly 
  hatched 
  caterpillars 
  pro- 
  

   duced 
  the 
  following 
  quantities 
  of 
  silk 
  : 
  4 
  feet 
  6 
  inches, 
  9 
  feet 
  7 
  inches, 
  

   38 
  feet 
  2 
  inches, 
  and 
  69 
  feet 
  4 
  inches. 
  Older 
  first-stage 
  caterpillars 
  

   spun 
  : 
  53 
  feet 
  2 
  inches, 
  24 
  feet 
  2 
  inches, 
  3 
  feet 
  2 
  inches, 
  6 
  feet 
  4 
  inches, 
  

   7 
  feet, 
  25 
  feet 
  3 
  inches, 
  and 
  22 
  feet 
  6 
  inches. 
  The 
  record 
  indicates 
  

   that 
  some 
  of 
  the 
  caterpillars 
  could 
  not 
  be 
  induced 
  to 
  spin, 
  but 
  from 
  

   the 
  figures 
  given 
  the 
  quantity 
  of 
  silk 
  spun 
  by 
  newly 
  hatched 
  first- 
  

   stage 
  caterpillars 
  ranged 
  from 
  4 
  feet 
  6 
  inches 
  to 
  G9 
  feet 
  4 
  inches, 
  

   giving 
  an 
  average 
  of 
  30 
  feet 
  3 
  inches, 
  while 
  for 
  caterpillars 
  in 
  the 
  

   same 
  stage 
  that 
  were 
  a 
  little 
  older 
  the 
  record 
  was 
  from 
  3 
  feet 
  2 
  inches 
  

   to 
  53 
  feet 
  2 
  inches, 
  giving 
  an 
  average 
  of 
  23 
  feet 
  8 
  inches. 
  

  

  These 
  experiments 
  were 
  repeated 
  in 
  the 
  spring 
  of 
  1911. 
  An 
  at- 
  

   tempt 
  was 
  made 
  to 
  use 
  a 
  reel 
  similar 
  to 
  the 
  one 
  already 
  mentioned, 
  

   but 
  much 
  difficulty 
  was 
  experienced, 
  even 
  when 
  the 
  larva? 
  were 
  

   placed 
  in 
  warm 
  sunshine 
  and 
  when 
  spinning 
  was 
  encouraged 
  by 
  

   using 
  an 
  electric 
  fan 
  to 
  make 
  a 
  strong 
  air 
  current. 
  It 
  was 
  found 
  

   thai 
  no 
  spinning 
  would 
  take 
  place 
  when 
  the 
  temperature 
  was 
  low. 
  

   Unless 
  the 
  larva' 
  were 
  constantly 
  disturbed, 
  they 
  would 
  climb 
  up 
  the 
  

   threads 
  which 
  they 
  had 
  spun, 
  and 
  after 
  this 
  commenced 
  it 
  was 
  diffi- 
  

   cult 
  to 
  induce 
  them 
  to 
  spin 
  more 
  or 
  to 
  prevent 
  them 
  from 
  crawling 
  

   up 
  to 
  the 
  attachment 
  on 
  the 
  reel. 
  The 
  same 
  thing 
  occurs 
  in 
  nature, 
  

   and 
  it 
  is 
  quite 
  common 
  to 
  find 
  first-stage 
  caterpillars 
  suspended 
  

   from 
  the 
  trees 
  hearing 
  a 
  small 
  mas^ 
  of 
  white 
  material 
  beneath 
  the 
  

   mouth 
  cavity 
  or 
  partly 
  around 
  the 
  first 
  pair 
  of 
  legs, 
  (lose 
  exaniina- 
  

  

  