﻿THE 
  DISPERSION 
  OF 
  THE 
  GIPSY 
  MOTH. 
  27 
  

  

  LABORATORY 
  EXPERIMENTS. 
  

  

  On 
  May 
  3, 
  1911, 
  1,500 
  gipsy-moth 
  caterpillars, 
  12 
  hours 
  old 
  or 
  less, 
  

   were 
  placed 
  in 
  a 
  glass 
  battery 
  jar, 
  which 
  in 
  turn 
  was 
  placed 
  for 
  a 
  

   short 
  time 
  in 
  the 
  laboratory 
  yard 
  where 
  the 
  temperature 
  was 
  4G° 
  F. 
  

   There 
  was 
  no 
  activity, 
  and 
  later, 
  when 
  the 
  jar 
  was 
  placed 
  in 
  the 
  

   basement 
  where 
  the 
  temperature 
  was 
  48° 
  to 
  50° 
  F., 
  the 
  same 
  result 
  

   was 
  observed. 
  The 
  jar 
  was 
  then 
  placed 
  in 
  the 
  incubator 
  and 
  the 
  

   following 
  notes 
  were 
  made 
  by 
  Mr. 
  Collins: 
  

  

  The 
  temperature 
  was 
  held 
  at 
  degrees 
  mentioned 
  for 
  from 
  10 
  to 
  20 
  minutes. 
  

  

  52° 
  F. 
  No 
  motion 
  unless 
  larva? 
  were 
  disturbed; 
  then 
  it 
  was 
  very 
  slight. 
  

  

  54° 
  F. 
  No 
  motion 
  in 
  mass 
  of 
  larvae. 
  Two 
  crawled 
  5 
  inches. 
  

  

  56° 
  F. 
  No 
  motion 
  in 
  mass 
  of 
  larva?. 
  

  

  r>S° 
  F. 
  No 
  motion 
  in 
  mass 
  of 
  larvae. 
  Two 
  have 
  crawled 
  1 
  inch 
  in 
  10 
  minutes. 
  

  

  (50° 
  F. 
  No 
  motion 
  in 
  mass 
  of 
  larvae. 
  Two 
  have 
  crawled 
  6 
  inches; 
  two. 
  4 
  

   inches. 
  

  

  62° 
  F. 
  No 
  motion 
  in 
  mass 
  of 
  larva-. 
  Fifteen 
  larvae 
  crawling. 
  One 
  climbing 
  

   up 
  thread 
  that 
  had 
  been 
  spun. 
  One 
  spun 
  1 
  inch 
  and 
  crawled 
  up. 
  One 
  spun 
  

   * 
  inch. 
  

  

  64° 
  F. 
  Motion 
  in 
  mass 
  noticeable. 
  Fifty 
  larvae 
  crawled 
  actively, 
  a 
  few 
  spin- 
  

   ning. 
  

  

  60° 
  F. 
  Motion 
  in 
  mass 
  more 
  noticeable. 
  One 
  hundred 
  larvae 
  crawling, 
  a 
  few 
  

   spinning 
  short 
  threads. 
  

  

  68° 
  F. 
  Mass 
  of 
  larva? 
  active. 
  Eight 
  larvae 
  have 
  each 
  spun 
  7* 
  inches. 
  

  

  70° 
  F. 
  Almost 
  every 
  larva 
  moving. 
  

  

  72° 
  F. 
  Caterpillars 
  all 
  crawling 
  about 
  and 
  spreading 
  freely. 
  

  

  74° 
  F. 
  Many 
  spinning 
  and 
  hanging 
  by 
  threads. 
  

  

  76° 
  F. 
  Larva? 
  very 
  active 
  and 
  spinning. 
  

  

  78° 
  P. 
  Half 
  of 
  the 
  larva? 
  have 
  crawled 
  from 
  jar. 
  All 
  active. 
  They 
  spin 
  

   rapidly. 
  

  

  80° 
  F. 
  Active 
  and 
  spinning 
  freely. 
  

  

  84° 
  F. 
  About 
  the 
  same 
  as 
  80° 
  F. 
  

  

  88° 
  F. 
  Possibly 
  a 
  little 
  more 
  active. 
  

  

  92° 
  F. 
  Larva? 
  crawling 
  and 
  spinning 
  more 
  rapidly. 
  

  

  96° 
  F. 
  All 
  caterpillars 
  have 
  left, 
  the 
  jar 
  and 
  arc 
  on 
  the 
  move. 
  It 
  took 
  this 
  

   temperature 
  to 
  force 
  all 
  of 
  them 
  from 
  the 
  jar. 
  

  

  100° 
  F. 
  Larva? 
  very 
  active. 
  They 
  crawl 
  very 
  fast, 
  but 
  spin 
  little. 
  

  

  100° 
  F. 
  Same 
  as 
  100° 
  F. 
  

  

  108° 
  F. 
  Larvae 
  gathered 
  in 
  masses; 
  loss 
  crawling 
  and 
  spinning. 
  

  

  110° 
  F. 
  Little 
  crawling; 
  larva? 
  squirming 
  in 
  the 
  masses. 
  

  

  After 
  holding 
  the 
  temperature 
  for 
  two 
  hours 
  at 
  110° 
  F. 
  the 
  incubator 
  was 
  

   cooled 
  down 
  to 
  82° 
  F. 
  Twenty-five 
  (load 
  larva? 
  wore 
  found, 
  and 
  the 
  remainder 
  

   were 
  not 
  very 
  active. 
  The 
  temperature 
  was 
  tbcn 
  raised 
  again 
  to 
  110° 
  F. 
  At 
  

   92° 
  F. 
  larva 
  1 
  became 
  more 
  active, 
  and 
  tins 
  continued 
  until 
  100° 
  F. 
  was 
  reached. 
  

  

  Most 
  of 
  them 
  showed 
  the 
  effects 
  of 
  the 
  previous 
  high 
  temperature. 
  

  

  A 
  set 
  of 
  observations 
  was 
  also 
  made 
  May 
  3, 
  L911, 
  on 
  first-stage 
  

  

  caterpillars 
  which 
  hatched 
  April 
  '2'2 
  and 
  were 
  feeding 
  in 
  trays 
  at 
  the 
  

   Laboratory. 
  No 
  motion 
  was 
  noted 
  at 
  54° 
  F.,l>ut 
  when 
  the 
  temperature 
  

   rose 
  to 
  62° 
  F. 
  they 
  crawled 
  slowly 
  about 
  on 
  the 
  food. 
  At 
  68 
  F. 
  

   they 
  were 
  Crawling 
  freely, 
  and 
  activity 
  increased 
  as 
  the 
  temperature 
  

   rose. 
  

  

  