﻿THE 
  DISPERSION 
  OF 
  THE 
  GIPSY 
  MOTH, 
  

  

  INTRODUCTION. 
  

  

  The 
  dispersion 
  of 
  any 
  insect 
  that 
  has 
  been 
  introduced, 
  accidentally 
  

   or 
  otherwise, 
  into 
  a 
  new 
  country 
  offers 
  an 
  interesting 
  opportunity 
  to 
  

   study 
  the 
  elements 
  which 
  aid 
  in 
  bringing 
  about 
  its 
  transmission 
  from 
  

   point 
  to 
  point 
  within 
  that 
  country, 
  and 
  this 
  is 
  particularly 
  true 
  con- 
  

   cerning 
  one 
  of 
  so 
  great 
  economic 
  importance 
  as 
  is 
  the 
  gipsy 
  moth. 
  

   When 
  the 
  first 
  work 
  to 
  suppress 
  this 
  insect 
  was 
  taken 
  up 
  in 
  the 
  early 
  

   nineties 
  an 
  attempt 
  was 
  made 
  to 
  determine 
  all 
  the 
  means 
  by 
  which 
  

   the 
  insect 
  was 
  spread, 
  and 
  since 
  that 
  time 
  any 
  data 
  bearing 
  on 
  the 
  

   spread 
  of 
  the 
  pest 
  have 
  been 
  eagerly 
  sought 
  and 
  carefully 
  studied 
  in 
  

   the 
  hope 
  that 
  better 
  methods 
  could 
  be 
  found 
  for 
  its 
  control. 
  The 
  

   region 
  surrounding 
  Medford, 
  Mass., 
  where 
  the 
  gipsy 
  moth 
  was 
  in- 
  

   troduced 
  in 
  1869, 
  is 
  the 
  center 
  of 
  one 
  of 
  the 
  most 
  thickly 
  populated 
  

   sections 
  of 
  the 
  United 
  States; 
  hence 
  there 
  was 
  an 
  unusual 
  oppor- 
  

   tunity 
  for 
  the 
  spread 
  of 
  the 
  insect 
  by 
  artificial 
  means. 
  In 
  spite 
  of 
  

   the 
  work 
  that 
  has 
  been 
  done 
  and 
  the 
  observations 
  that 
  have 
  been 
  

   recorded 
  it 
  has 
  remained 
  until 
  the 
  last 
  two 
  years 
  for 
  a 
  demonstra- 
  

   tion 
  to 
  be 
  made 
  of 
  the 
  manner 
  by 
  which 
  this 
  insect 
  is 
  spread, 
  to 
  the 
  

   greatest 
  extent, 
  by 
  natural 
  means. 
  

  

  MEANS 
  BY 
  WHICH 
  INSECTS 
  ARE 
  SPREAD. 
  

  

  One 
  of 
  the 
  principal 
  methods 
  of 
  insect 
  locomotion 
  and 
  of 
  spread- 
  

   ing 
  is 
  by 
  flying, 
  and 
  there 
  is 
  little 
  chance 
  of 
  preventing 
  the 
  spread 
  

   of 
  a 
  strong-flying 
  introduced 
  species 
  which 
  has 
  become 
  thoroughly 
  

   established. 
  The 
  continued 
  spread 
  of 
  the 
  elm 
  leaf-beetle 
  and 
  of 
  the 
  

   brown-tail 
  moth 
  illustrates 
  how 
  flying 
  insects 
  are 
  dispersed. 
  

  

  There 
  is, 
  however, 
  another 
  class 
  of 
  insects 
  which 
  does 
  not 
  spread 
  

   by 
  flying. 
  Several 
  distinct 
  types 
  exist, 
  and 
  among 
  them 
  may 
  be 
  

   mentioned 
  such 
  insects 
  as 
  the 
  San 
  Jose 
  scale 
  and 
  other 
  closely 
  re- 
  

   lated 
  species. 
  The 
  structure 
  of 
  the 
  females 
  of 
  this 
  group 
  is 
  such 
  

   that 
  they 
  remain 
  fixed 
  before 
  becoming 
  sexually 
  mature; 
  hence 
  the 
  

   distribution 
  of 
  the 
  species 
  is 
  confined, 
  so 
  far 
  as 
  natural 
  means 
  is 
  

   concerned, 
  to 
  the 
  dissemination 
  of 
  the 
  young, 
  which 
  have 
  the 
  ability 
  

   to 
  move 
  about 
  for 
  a 
  limited 
  period. 
  The 
  adult 
  insects 
  are 
  spread 
  

   by 
  artificial 
  means 
  on 
  nursery 
  slock 
  and 
  on 
  living 
  trees 
  or 
  shrubs 
  (hat 
  

   arc 
  shipped 
  from 
  one 
  locality 
  to 
  another 
  for 
  planting 
  or 
  propagation. 
  

   The 
  brown-tail 
  moth 
  has 
  also 
  been 
  distributed 
  on 
  nursery 
  stock, 
  hut 
  

   it 
  is 
  carried 
  in 
  this 
  way 
  while 
  the 
  small 
  caterpillars 
  are 
  in 
  the 
  

   hibernating 
  webs 
  where 
  they 
  pass 
  the 
  winter. 
  

  

  