﻿THE 
  ARMY 
  WORM: 
  NUMBER 
  OF 
  ANNUAL 
  BROODS. 
  121 
  

  

  tember 
  two 
  worms 
  were 
  found. 
  September 
  23 
  a 
  nearly 
  full-grown 
  worm 
  

   was 
  found 
  feeding 
  upon 
  a 
  head 
  of 
  timothy, 
  and 
  the 
  same 
  day 
  three 
  more 
  

   were 
  found 
  hiding 
  beneath 
  a 
  board^ 
  one 
  of 
  them 
  tachinized. 
  Of 
  the 
  

   worms 
  found 
  early 
  in 
  September, 
  one 
  pupated 
  September 
  22, 
  and 
  issued 
  

   as 
  a 
  moth 
  some 
  time 
  before 
  the 
  15th 
  of 
  October 
  ; 
  the 
  exact 
  date 
  of 
  issue 
  

   is 
  not 
  known. 
  Of 
  the 
  worms 
  found 
  September 
  23, 
  one 
  pupated 
  a 
  week 
  

   later 
  and 
  issued 
  as 
  a 
  moth 
  October 
  22 
  ; 
  the 
  rest 
  died. 
  October 
  29 
  a 
  

   worm 
  measuring 
  one-half 
  inch 
  in 
  length, 
  or 
  less 
  than 
  half 
  grown, 
  was 
  

   found. 
  November 
  1 
  four 
  more 
  were 
  found, 
  one 
  seven-eighths 
  of 
  an 
  inch 
  

   in 
  length, 
  and 
  the 
  rest 
  three-fourths 
  of 
  an 
  inch 
  long. 
  November 
  4 
  an- 
  

   other 
  was 
  found 
  three-eighths 
  of 
  an 
  inch 
  long, 
  and 
  on 
  the 
  5th 
  one 
  more 
  

   measuring 
  one-half 
  inch. 
  TJiese 
  last 
  worms 
  were 
  all 
  found, 
  according 
  to 
  

   Mr. 
  Ooquillett, 
  under 
  or 
  in 
  shocks 
  of 
  corn, 
  and 
  we 
  think 
  would 
  evidently 
  

   have 
  hibernated 
  in 
  these 
  localities. 
  

  

  Thus, 
  even 
  admitting 
  the 
  injurious 
  brood 
  of 
  July 
  to 
  have 
  been 
  only 
  

   the 
  second 
  (hibernating 
  worms 
  constituting 
  the 
  first), 
  we 
  have 
  three 
  

   broods 
  m 
  northern 
  Illinois 
  plainly 
  demonstrated, 
  the 
  worms 
  of 
  August 
  

   and 
  September 
  constituting 
  the 
  third 
  brood 
  and 
  the 
  offspring 
  of 
  the 
  

   October 
  moths 
  the 
  hibernating 
  brood 
  or 
  the 
  first 
  of 
  thei^resent 
  season. 
  

   The 
  case 
  is 
  made 
  all 
  the 
  stronger 
  when 
  we 
  consider 
  that 
  a 
  half-grown 
  

   worm 
  was 
  found 
  August 
  23, 
  which, 
  had 
  it 
  been 
  reared 
  to 
  the 
  perfect 
  

   state, 
  would 
  probably 
  have 
  given 
  forth 
  the 
  moth 
  before 
  the 
  first 
  of 
  Oc- 
  

   tober. 
  

  

  We 
  have 
  already 
  shown 
  that 
  the 
  injurious 
  brood 
  is 
  usually 
  the 
  second, 
  

   but 
  have 
  also 
  given 
  instances 
  which 
  indicate 
  that 
  it 
  is 
  occasionally 
  the 
  

   third. 
  We 
  have 
  every 
  reason 
  to 
  suppose 
  that 
  Thomas's 
  estimated 
  average 
  

   length 
  of 
  life 
  of 
  the 
  individual 
  — 
  seventy-seven 
  days 
  — 
  is 
  too 
  long, 
  even 
  for 
  

   the 
  more 
  northern 
  portions 
  of 
  the 
  country. 
  The 
  experience 
  of 
  every 
  ento- 
  

   mologist 
  will 
  show 
  that 
  in 
  summer 
  an 
  insect 
  will 
  occupy 
  a 
  longer 
  time 
  

   in 
  undergoing 
  its 
  transformations 
  within 
  the 
  breeding 
  cage 
  than 
  in 
  the 
  

   field 
  under 
  natural 
  conditions, 
  and 
  yet 
  Thomas 
  has 
  taken 
  the 
  vivarium 
  

   life 
  as 
  the 
  minhmimJ^ 
  We 
  have 
  shown 
  by 
  exi)eriment 
  that 
  indoors 
  

  

  35Mr. 
  Liutnor's 
  paper 
  on 
  a 
  somewhat 
  similar 
  subject, 
  viz., 
  the 
  life 
  dnratioli 
  in 
  Heterocera, 
  gave 
  a 
  

   long 
  series 
  of 
  caieful 
  notes 
  of 
  collectings, 
  from 
  which 
  he 
  concluded 
  that 
  the 
  average 
  duration 
  of 
  moths 
  

   is 
  from 
  two 
  to 
  three 
  weeks 
  in 
  summer. 
  The 
  paper 
  gave 
  rise 
  to 
  some 
  extended 
  remarks 
  from 
  Messrs. 
  

   Thomas, 
  Mann, 
  Riley, 
  and 
  others. 
  Mr. 
  Thomas 
  thought 
  that 
  the 
  knowledge 
  of 
  tl)e 
  term 
  of 
  life 
  in 
  the 
  

   iuiago 
  was 
  of 
  less 
  value, 
  fioni 
  an 
  economic 
  standpoint, 
  than 
  that 
  of 
  the 
  individual 
  in 
  all 
  its 
  states. 
  In 
  

   endeavoring 
  to 
  ascertain 
  tliis 
  duratiou 
  in 
  Leucania 
  unixmncta, 
  he 
  had 
  come 
  to 
  the 
  conclusion 
  that 
  it 
  

   was 
  ahout 
  seventy-seven 
  days. 
  This 
  conclusion, 
  based 
  on 
  calculations 
  from 
  recorded 
  appearances 
  of 
  

   the 
  insect, 
  was 
  in 
  opposition 
  to 
  the 
  only 
  actual 
  experiments 
  which 
  are 
  on 
  record, 
  viz., 
  those 
  by 
  Mr. 
  

   Riley 
  in 
  the 
  Eighth 
  and 
  Ninth 
  Reports 
  on 
  the 
  Insects 
  of 
  Missouri, 
  which 
  show 
  that 
  the 
  term 
  of 
  life 
  in 
  

   summer 
  barely 
  extends 
  over 
  half 
  as 
  many 
  days. 
  In 
  fact, 
  all 
  our 
  expeiience 
  as 
  to 
  the 
  .summer 
  duration 
  

   of 
  life 
  in 
  this 
  species 
  shows 
  that 
  the 
  states 
  of 
  egg, 
  larva, 
  chrysalis, 
  and 
  imago 
  average 
  forty 
  days. 
  

   Mr. 
  Thomas 
  argued 
  that 
  insects 
  in 
  confinement 
  develop 
  more 
  rapidly 
  than 
  in 
  freedom. 
  Mr. 
  Riley 
  gave 
  

   his 
  experience 
  as 
  opposed 
  to 
  the 
  statement 
  : 
  insects 
  reared 
  in 
  confinement 
  during 
  the 
  summer 
  are 
  likely 
  

   to 
  develop 
  moi'e 
  slowly 
  than 
  in 
  freedom, 
  for 
  the 
  obvious 
  reason 
  that 
  those 
  in 
  freedom 
  get 
  more 
  sun- 
  

   light 
  and 
  constantly 
  have 
  a 
  supply 
  of 
  fresh 
  food 
  at 
  hand, 
  and 
  this 
  will 
  hold 
  equally 
  true 
  with 
  the 
  

   changes 
  that 
  take 
  place 
  underground, 
  for 
  the 
  mean 
  temptjrature 
  of 
  the 
  soil, 
  during 
  summer, 
  is 
  evidently 
  

   greater 
  outdoors 
  than 
  indoors. 
  Expeiience 
  shows, 
  moreover, 
  that 
  in 
  this 
  question 
  everything 
  depends 
  

   en 
  the 
  time 
  of 
  year, 
  the 
  chaiacter 
  of 
  the 
  weather 
  and 
  other 
  surrounding 
  conditions, 
  there 
  being 
  a 
  wide 
  

   tiinge 
  in 
  the 
  duration 
  of 
  life 
  in 
  the 
  same 
  species.— 
  (Adapted 
  ivova. 
  Amer. 
  Naturalist, 
  Nov., 
  1881, 
  p. 
  912). 
  

  

  