﻿704 
  EEPORT 
  UNITED 
  STATES 
  GEOLOGICAL 
  SUEVEY. 
  

  

  five 
  worms 
  hatch, 
  probably 
  only 
  three 
  or 
  four 
  perpetuate 
  their 
  kind 
  ; 
  

   and 
  so 
  on 
  throughout 
  the 
  insect-world. 
  The 
  struggle 
  for 
  existence 
  is 
  

   so 
  great, 
  each 
  species 
  suffering 
  from 
  adverse 
  climatic 
  causes 
  and 
  insect- 
  

   enemies, 
  that 
  but 
  a 
  small 
  proportion 
  survive 
  the 
  perils 
  of 
  infancy 
  and 
  child- 
  

   hood, 
  so 
  to 
  speak. 
  Were 
  it 
  not 
  so, 
  the 
  world 
  would 
  be 
  overrun 
  with 
  

   prepotent 
  animals 
  and 
  plants. 
  The 
  increase 
  and 
  great 
  abundance 
  of 
  

   the 
  few 
  species 
  are 
  an 
  indication 
  of 
  the 
  intense 
  struggle 
  for 
  existence 
  

   by 
  which 
  the 
  many 
  alone 
  maintain 
  their 
  livelihood. 
  

  

  Remedies. 
  — 
  If 
  lands 
  are 
  burned 
  over 
  in 
  the 
  dead 
  of 
  the 
  year 
  where 
  

   these 
  eggs 
  or 
  pupae 
  or 
  moths 
  abound, 
  which 
  is 
  the 
  best 
  remedy 
  we 
  can 
  

   apply 
  to 
  keep 
  off 
  or 
  kill 
  off 
  this 
  moth, 
  the 
  fire 
  will 
  certainly 
  kill 
  the 
  

   chrysalids 
  just 
  below 
  the 
  roots 
  of 
  the 
  grass, 
  as 
  it 
  surely 
  will 
  the 
  eggs 
  

   on 
  the 
  stalks 
  or 
  the 
  moths 
  nestling 
  among 
  them. 
  Tract«s 
  of 
  land 
  in 
  

   Maine 
  thus 
  burned 
  over 
  in 
  the 
  spring 
  of 
  1861 
  escaped 
  the 
  army- 
  worm 
  in 
  

   the 
  summer, 
  while 
  farms 
  near 
  by 
  suffered 
  from 
  the 
  incursions 
  of 
  worms 
  

   from 
  the 
  unburned 
  grass-lands 
  around. 
  

  

  Ditching, 
  or 
  making 
  a 
  deep 
  trench 
  with 
  steep 
  or 
  undermining 
  sides, 
  

   especially 
  efficacious 
  in 
  sandy 
  soils, 
  will 
  do 
  much 
  toward 
  keeping 
  them 
  

   out 
  of 
  fields 
  of 
  grain. 
  People 
  have 
  also 
  laid 
  tar 
  in 
  the 
  bottom 
  of 
  

   ditches, 
  laid 
  trains 
  of 
  guano, 
  and 
  made 
  bonfires 
  in 
  them. 
  By 
  turning 
  

   fowl 
  and 
  hogs 
  into 
  fields 
  just 
  as 
  the 
  caterpillar 
  is 
  going 
  into 
  the 
  earth 
  

   to 
  pupate, 
  great 
  numbers 
  can 
  be 
  destroyed, 
  and 
  the 
  hogs 
  and 
  hens 
  will 
  

   grow 
  fat 
  on 
  them. 
  

  

  Enemies. 
  — 
  That 
  birds 
  of 
  different 
  kinds 
  feed 
  on 
  these 
  caterpillars 
  has 
  

   been 
  noticed. 
  There 
  are 
  also 
  night-birds 
  that 
  catch 
  the 
  moths 
  as 
  they 
  

   fly. 
  Both 
  the 
  larva 
  and 
  moth 
  are 
  exposed 
  on 
  every 
  hand 
  to 
  the 
  attacks 
  

   of 
  other 
  insects, 
  such 
  as 
  the 
  dragon-flies, 
  which 
  are 
  continually 
  on 
  the 
  

   wing, 
  especially 
  over 
  low 
  lands. 
  A 
  large 
  purple 
  beetle 
  with 
  rows 
  of 
  

   golden 
  spots 
  on 
  its 
  wing-covers, 
  the 
  Calosoma 
  calidmn, 
  which 
  is 
  very 
  

   common 
  in 
  grass-lands, 
  either 
  running 
  about 
  after 
  their 
  prey, 
  or 
  lying 
  ^ 
  

   on 
  the 
  watch 
  in 
  their 
  holes 
  among 
  the 
  grass, 
  makes 
  great 
  havoc 
  among 
  

   the 
  army-worm, 
  and 
  not 
  only 
  the 
  beetle, 
  but 
  its 
  larva, 
  which 
  is 
  more 
  

   voracious, 
  if 
  possible. 
  

  

  Ants 
  are 
  known 
  to 
  destroy 
  the 
  army-worm. 
  I 
  am 
  indebted 
  to 
  Mr. 
  H. 
  

   I. 
  Hershs, 
  of 
  Eichmond, 
  Ind., 
  for 
  the 
  following 
  instance 
  : 
  ''In 
  June, 
  

   1875, 
  the 
  army-worms 
  took 
  possession 
  of 
  a 
  grass-plot 
  near 
  my 
  study- 
  

   window, 
  and 
  for 
  a 
  time 
  threatened 
  to 
  strip 
  it 
  of 
  every 
  vestige 
  of 
  green; 
  

   but 
  I 
  noticed 
  a 
  few 
  days 
  after 
  they 
  made 
  their 
  appearance 
  that 
  a 
  large 
  

   number 
  of 
  small 
  black 
  ants 
  were 
  waging 
  a 
  war 
  of 
  extermination 
  against 
  

   them, 
  which, 
  in 
  conjunction 
  with 
  the 
  unusually 
  wet 
  weather, 
  soon 
  put 
  

   a 
  stop 
  to 
  their 
  depredations." 
  

  

  But 
  undoubtedly 
  the 
  grand 
  check 
  that 
  nature 
  has 
  imposed 
  upon 
  the 
  

   too 
  great 
  increase 
  of 
  caterpillars 
  are 
  their 
  parasites, 
  or 
  those 
  ichneu- 
  

   mon-flies 
  belonging 
  to 
  the 
  great 
  order 
  Hymenoptera.. 
  and 
  two 
  species 
  

   of 
  Diptera, 
  or 
  true 
  flies, 
  which 
  lay 
  their 
  eggs 
  on 
  the 
  outside 
  of 
  the 
  

   caterpillar. 
  The 
  young 
  hatching 
  out 
  feeds 
  on 
  the 
  fatty 
  tissues 
  of 
  the 
  

   caterpillar, 
  which 
  lives 
  just 
  along 
  time 
  enough 
  for 
  the 
  parasite 
  

   within 
  to 
  come 
  to 
  maturity. 
  The 
  larger 
  ichneumons 
  only 
  live 
  singly 
  in 
  

   the 
  body 
  of 
  the 
  caterpillar, 
  while 
  as 
  many 
  as 
  a 
  hundred 
  of 
  the 
  minute 
  

   species 
  have 
  been 
  seen 
  to 
  emerge 
  from 
  the 
  dead 
  larva-skin, 
  their 
  cocoons 
  

   placed 
  side 
  by 
  side 
  within. 
  

  

  We 
  first 
  notice 
  a 
  large 
  species 
  which 
  Mr. 
  Shurtleff 
  raised 
  from 
  the 
  

   army-worm 
  between 
  the 
  first 
  and 
  middle 
  of 
  September. 
  

  

  Ophion 
  purgatus 
  Say, 
  This 
  genus 
  of 
  ichneumons 
  has 
  a 
  slender 
  

   body, 
  with 
  long 
  filiform 
  antennsB. 
  The 
  thorax 
  above 
  oval, 
  and 
  as 
  wide 
  

   as 
  the 
  head. 
  The 
  legs 
  are 
  long 
  and 
  slender; 
  but 
  the 
  most 
  apparent 
  

  

  