﻿776 
  EEPORT 
  UNITED 
  STATES 
  GEOLOGICAL 
  SURVEY. 
  

  

  caterpillar 
  resembles 
  the 
  germetrid 
  or 
  measuring'-worms 
  in 
  its 
  gait. 
  In 
  , 
  

   this 
  way 
  it 
  can 
  readily 
  be 
  distinguished 
  from 
  either 
  the 
  northern 
  army- 
  4; 
  

   worm 
  or 
  the 
  boll-worm. 
  Its 
  body 
  is 
  thickest 
  in 
  the 
  middle, 
  very 
  hairy, 
  I 
  

   green, 
  dotted 
  with 
  black 
  along 
  a 
  subdorsal 
  yellowish 
  line, 
  and 
  with 
  black 
  

   dots 
  beneath. 
  

  

  " 
  In 
  Central 
  Alabama," 
  says 
  Grote, 
  "I 
  have 
  watched 
  the 
  growth 
  of 
  

   the 
  worms 
  on 
  the 
  cotton-plant. 
  The 
  worm 
  appears 
  there 
  in 
  certain 
  

   seasons, 
  as 
  early 
  as 
  the 
  latter 
  part 
  of 
  June. 
  After 
  feeding 
  for 
  a 
  period 
  'j 
  

   of 
  about 
  fourteen 
  days, 
  the 
  cotton-wqrms 
  commence 
  preparations 
  for 
  1 
  

   shedding 
  their 
  skin 
  to 
  pass 
  into 
  the 
  chrysalis 
  stage 
  of 
  growth. 
  For 
  this 
  

   they 
  spin 
  a 
  few 
  loose 
  threads 
  of 
  silk 
  on 
  the 
  plant 
  itself, 
  which 
  they 
  rarely 
  , 
  

   forsake 
  for 
  that 
  purpose. 
  Within 
  this 
  light 
  web 
  the 
  lost 
  larvae 
  skin 
  is 
  

   thrown 
  off, 
  and 
  the 
  brown 
  chrysalis 
  skin 
  is 
  exposed. 
  In 
  this 
  state 
  the 
  

   worm 
  passes 
  from 
  a 
  week 
  to 
  ten 
  days." 
  

  

  Eiley 
  states 
  that, 
  "according 
  to 
  the 
  best 
  authority, 
  there 
  are 
  three 
  

   different 
  broods 
  of 
  worms 
  during 
  the 
  year, 
  the 
  first. 
  appearing 
  in 
  June 
  

   or 
  July, 
  and 
  the 
  last 
  which 
  does 
  the 
  most 
  damage, 
  appearing 
  in 
  August 
  i 
  

   or 
  September, 
  or 
  even 
  later." 
  

  

  Like 
  our 
  northern 
  army-worm 
  {Leucmiia 
  unipuncta), 
  the 
  cotton 
  army- 
  

   worm, 
  the 
  early 
  stages 
  of 
  the 
  caterpillar 
  having 
  been 
  unnoticed, 
  owing 
  

   to 
  the 
  fact 
  that 
  it 
  simulates 
  the 
  leaves 
  on 
  which 
  it 
  feeds 
  and 
  is 
  so 
  small, 
  i 
  

   becomes 
  suddenly 
  visible 
  in 
  great 
  numbers 
  in 
  a 
  single 
  day, 
  committing 
  

   the 
  greatest 
  havoc 
  in 
  a 
  few 
  hours. 
  I 
  extract 
  the 
  following 
  account 
  of 
  

   an 
  invasion 
  of 
  these 
  cotton-worms, 
  written 
  by 
  Prof. 
  J. 
  Darby, 
  of 
  Auburn, 
  | 
  

   Ala., 
  and 
  quoted 
  in 
  my 
  Guide 
  : 
  " 
  Saturday, 
  September 
  19, 
  I 
  was 
  in 
  

   the 
  field 
  examining 
  the 
  forms 
  (buds 
  before 
  flowering) 
  and 
  the 
  young 
  

   bolls 
  (fruit 
  after 
  the 
  floral 
  organs 
  have 
  fallen 
  oif 
  ). 
  I 
  examined 
  all 
  care- 
  

   fully, 
  with 
  no 
  signs 
  of 
  eggs 
  or 
  worms. 
  On 
  Sunday 
  I 
  did 
  not 
  see 
  it. 
  On 
  

   Monday 
  I 
  passed 
  it 
  as 
  usual 
  and 
  observed 
  nothing 
  unusual. 
  On 
  Tues- 
  

   day 
  morning 
  I 
  passed 
  it 
  and 
  noticed 
  nothing 
  unusual. 
  On 
  Tuesday 
  

   noon 
  every 
  plant 
  in 
  the 
  field 
  was 
  stri^Dped 
  of 
  all 
  its 
  upper 
  leaves, 
  not 
  

   one 
  remaining 
  as 
  far 
  as 
  could 
  be 
  seen, 
  and 
  the 
  plants 
  were 
  covered 
  with 
  

   millions 
  of 
  worms. 
  I 
  counted 
  on 
  one 
  plant 
  forty-six 
  worms. 
  They 
  com- 
  

   mence 
  at 
  the 
  top 
  of 
  the 
  plant, 
  eating 
  every 
  leaf. 
  When 
  the 
  leaves 
  were 
  

   gone 
  they 
  attacked 
  the 
  young 
  bolls, 
  eating 
  through 
  the 
  perianth 
  and 
  

   consuming 
  the 
  young 
  cotton. 
  In 
  the 
  course 
  of 
  four 
  days 
  the 
  work 
  was 
  

   done. 
  They 
  did 
  not 
  touch 
  the 
  grape, 
  nor 
  any 
  other 
  jjlaut 
  in 
  the 
  field. 
  

   Many 
  left 
  the 
  field 
  and 
  thousands 
  were 
  in 
  the 
  road 
  and 
  on 
  the 
  fences, 
  

   but 
  not 
  one 
  in 
  a 
  thousand 
  thus 
  escaped. 
  To-day, 
  September 
  23, 
  there 
  ! 
  

   is 
  scarcely 
  one 
  to 
  be 
  seen. 
  Their 
  disappearance 
  is 
  as 
  mysterious 
  as 
  ' 
  

   their 
  coming. 
  They 
  have 
  left 
  no 
  signs 
  that 
  I 
  can 
  see, 
  either 
  on 
  the 
  stalks 
  » 
  

   or 
  in 
  the 
  ground. 
  They 
  have 
  extended 
  over 
  hundreds 
  of 
  miles, 
  and 
  1 
  

   nothing 
  has 
  proved 
  a 
  barrier 
  to 
  them, 
  having 
  been 
  as 
  destructive 
  on 
  

   islands 
  in 
  the 
  river 
  as 
  elsewhere. 
  One-third 
  of 
  the 
  cotton-crop 
  has 
  been 
  

   destroyed. 
  Nothing 
  of 
  the 
  kind 
  has 
  occurred 
  in 
  thirty 
  years 
  past 
  to 
  my 
  

   knowledge." 
  

  

  In 
  1788 
  the 
  cotton 
  army-worm 
  destroyed, 
  at 
  a 
  low 
  estimate, 
  200 
  tons 
  

   of 
  cotton 
  in 
  the 
  Bahamas 
  5 
  in 
  Georgia, 
  the 
  crop 
  was 
  destroyed 
  in 
  1793, 
  

   and 
  it 
  was 
  very 
  destructive 
  in 
  1800, 
  1804, 
  1825, 
  and 
  1826, 
  and 
  since 
  then 
  

   has 
  been 
  destructive 
  in 
  certain 
  localities 
  nearly 
  each 
  year, 
  though 
  not 
  

   always 
  in 
  the 
  same 
  State. 
  The 
  average 
  annual 
  loss 
  in 
  this 
  country 
  is 
  

   probably 
  some 
  years 
  $50,000,000. 
  So 
  great 
  is 
  the 
  annual 
  loss 
  that 
  it 
  

   would 
  be 
  well 
  if 
  the 
  cotton 
  States 
  would 
  each 
  employ 
  a 
  salaried 
  ento- 
  

   mologist 
  to 
  investigate 
  and 
  report 
  on 
  the 
  insects 
  injurious 
  to 
  the 
  cotton- 
  

   plant. 
  The 
  United 
  States 
  Government 
  should 
  also 
  employ 
  competent 
  

   entomological 
  talent, 
  and 
  have 
  the 
  subject 
  investigated 
  from 
  a 
  broad, 
  

  

  