﻿712 
  EEPORT 
  UNITED 
  STATES 
  GEOLOGICAL 
  SURVEY. 
  

  

  Parasites. 
  — 
  Artificial 
  means 
  of 
  driving 
  off 
  this 
  pest 
  bave 
  not 
  yet 
  been 
  

   contrived. 
  It 
  has 
  been 
  suggested 
  to 
  kindle 
  fires, 
  throw 
  on 
  damp 
  straw, 
  

   and 
  let 
  the 
  wind 
  carry 
  the 
  smoke 
  over 
  the 
  field. 
  

  

  But 
  the 
  external 
  enemies 
  of 
  this 
  aphis 
  are 
  ready 
  to 
  help 
  us. 
  The 
  

   lady-bugs, 
  coccinella, 
  as 
  larvse 
  and 
  beetles, 
  the 
  golden-eyed 
  Hie&^chrysopa, 
  

   as 
  larv£e, 
  have 
  been 
  seen 
  the 
  past 
  season 
  in 
  great 
  numbers 
  in 
  wheat- 
  

   fields, 
  busily 
  engaged 
  in 
  devouring 
  the 
  plant-lice. 
  ^. 
  

  

  These 
  minute 
  insects 
  have 
  also 
  their 
  internal 
  parasites, 
  little 
  icbneu- 
  l| 
  

   mons 
  of 
  the 
  genus 
  Aplddius. 
  We 
  have 
  to 
  go 
  again 
  to 
  Dr. 
  Fitch's 
  arti- 
  "' 
  

   cle 
  for 
  information 
  respecting 
  their 
  habits 
  : 
  

  

  " 
  On 
  many 
  of 
  the 
  wheat-heads, 
  may 
  at 
  present 
  (August 
  6) 
  be 
  noticed 
  i 
  

   from 
  one 
  to 
  a 
  half 
  dozen 
  or 
  more 
  of 
  these 
  lice, 
  which 
  are 
  very 
  large, 
  li 
  

   plumj), 
  and 
  swollen, 
  of 
  the 
  color 
  of 
  brown 
  paper, 
  standing 
  in 
  a 
  posture 
  

   so 
  perfectly 
  natural 
  you 
  suppose 
  they 
  are 
  alive. 
  Touch 
  them 
  with 
  the 
  

   point 
  of 
  a 
  pin, 
  you 
  find 
  they 
  are 
  dead. 
  Pick 
  off 
  a 
  part 
  of 
  their 
  brittle 
  

   skin 
  5 
  you 
  see 
  there 
  is 
  inside 
  a 
  white 
  maggot 
  doubled 
  together 
  like 
  a 
  < 
  

   ball. 
  Put 
  one 
  or 
  two 
  of 
  these 
  wheat-heads 
  in 
  a 
  vial, 
  closing 
  its 
  -mouth 
  tj 
  

   with 
  a 
  wad 
  of 
  cotton. 
  In 
  a 
  week's 
  time, 
  or 
  less, 
  you 
  find 
  running 
  fl 
  

   lively 
  about 
  in 
  the 
  vial 
  some 
  little 
  black 
  flies, 
  like 
  small 
  ants. 
  These 
  

   you 
  see 
  have 
  come 
  out 
  from 
  the 
  dead 
  lice, 
  through 
  a 
  circular 
  opening 
  

   which 
  has 
  been 
  cut 
  in 
  their 
  backs. 
  Drive 
  one 
  or 
  two 
  of 
  these 
  flies 
  into 
  

   another 
  vial, 
  and 
  introduce 
  to 
  them 
  a 
  wheat-head 
  having 
  some 
  fresh 
  lice. 
  

   See 
  how 
  the 
  fly 
  runs 
  about 
  them, 
  examining 
  them 
  with 
  its 
  antennte. 
  

   Having 
  found 
  one 
  adapted 
  to 
  its 
  wants, 
  watch 
  how 
  dexterously 
  it 
  

   curves 
  its 
  body 
  forward 
  under 
  its 
  breast, 
  bringing 
  the 
  tip 
  before 
  its 
  face, 
  

   as 
  if 
  to 
  take 
  accurate 
  aim 
  with 
  its 
  sting. 
  There, 
  the 
  aphis 
  gives 
  a 
  shrug, 
  

   the 
  fly 
  has 
  pricked 
  it 
  with 
  its 
  sting, 
  an 
  Qgg 
  has 
  been 
  lodged 
  under 
  its 
  

   skin, 
  from 
  which 
  will 
  grow 
  a 
  maggot 
  like 
  that 
  first 
  seen 
  inside 
  the 
  dead, 
  

   swollen 
  aphis. 
  And 
  thus 
  the 
  little 
  fly 
  runs 
  busily 
  around 
  among 
  the 
  

   lice 
  on 
  the 
  wheat-heads, 
  stinging 
  one 
  after 
  another, 
  till 
  it 
  exhausts 
  its 
  

   stock 
  of 
  eggs, 
  a 
  hundred 
  probably, 
  or 
  more, 
  thus 
  insuring 
  the 
  death 
  of 
  

   that 
  number 
  of 
  these 
  lice. 
  And 
  of 
  its 
  progeny, 
  fifty 
  it 
  may 
  be 
  supposed, 
  

   will 
  be 
  females, 
  by 
  which 
  five 
  thousand 
  more 
  will 
  be 
  destroyed. 
  We 
  

   thus 
  see 
  what 
  efficient 
  agents 
  these 
  parasites 
  are 
  in 
  subduing 
  the 
  insects 
  

   on 
  which 
  they 
  prey. 
  I 
  find 
  three 
  different 
  species 
  of 
  them 
  now 
  at 
  work 
  

   in 
  our 
  fields 
  destroying 
  this 
  grain-aphis." 
  

  

  The 
  "Wheat-Head 
  Army-Worm, 
  AJbilinea 
  Huebner.— 
  Injuring 
  tbe 
  heads 
  of 
  wheat, 
  

   rye, 
  aud 
  barley, 
  beginuing 
  at 
  the 
  base, 
  sometimes 
  the 
  center 
  of 
  the 
  ear, 
  soiiietimes 
  

   hollowing 
  out 
  the 
  soft 
  grains, 
  leaving 
  nothing 
  but 
  the 
  shell 
  and 
  the 
  chaff; 
  a 
  caterpil- 
  

   lar 
  resembling 
  the 
  northern 
  army-worm, 
  but 
  striped 
  with 
  sulphur-yellow 
  and 
  light 
  i 
  

   and 
  dark 
  brown. 
  ! 
  

  

  Though 
  this 
  is 
  a 
  common 
  aud 
  wide-spread 
  insect, 
  rangiugfrom 
  Maine 
  to 
  ' 
  

   Kansas 
  and 
  southward, 
  it 
  was 
  not 
  known 
  to 
  be 
  injurious 
  to 
  crops 
  until 
  

   1872, 
  when 
  it 
  was 
  found, 
  according 
  to 
  Eiley, 
  seriously 
  injuring 
  oats 
  in 
  ■ 
  

   Pennsylvania. 
  In 
  1874 
  and 
  1875 
  it 
  was 
  reported 
  to 
  injure 
  wheat 
  and 
  tim- 
  

   othy 
  heads 
  in 
  Maryland 
  and 
  Pennsylvania. 
  It 
  was 
  described 
  as 
  " 
  hollow- 
  

   ing 
  out 
  the 
  soft 
  grains 
  and 
  leaving 
  nothing 
  but 
  the 
  shell 
  and 
  the 
  chaff," 
  ' 
  

   and 
  " 
  in 
  some 
  rye-fields 
  theheads 
  are 
  almost 
  void 
  of 
  grains 
  and 
  the 
  ground 
  

   literally 
  covered 
  with 
  chaff, 
  and 
  that 
  late-sowed 
  rye 
  would 
  not 
  be 
  worth 
  

   the 
  harvesting 
  were 
  it 
  not 
  for 
  the 
  straw." 
  It 
  was 
  more 
  widely 
  destruc- 
  

   tive 
  in 
  the 
  Eastern 
  States 
  in 
  3875 
  than 
  in 
  1874. 
  June 
  14, 
  187G, 
  Mr. 
  J. 
  AV. 
  

   Eobson, 
  of 
  Dickinson 
  County, 
  Kansas, 
  wrote 
  Mr. 
  Eiley 
  that 
  for 
  ten 
  days 
  

   past 
  it 
  had 
  been 
  noticed 
  in 
  the 
  wheat. 
  " 
  The 
  caterpillars 
  begin 
  their 
  

   depredations 
  at 
  the 
  base 
  of 
  the 
  ear, 
  and 
  sometimes 
  near 
  the 
  center 
  of 
  the 
  

   ear. 
  Jn 
  one 
  field 
  that 
  I 
  examined 
  to-day 
  the 
  Caterpillars 
  were 
  abundant. 
  

  

  