﻿694 
  REPORT 
  UNITED 
  STATES 
  GEOLOGICAL 
  SURVEY. 
  

  

  and 
  brittle, 
  so 
  tbat 
  the 
  straw 
  above 
  the 
  disease 
  is 
  impoverished, 
  and 
  

   seldom 
  produces 
  any 
  grain. 
  Suckers, 
  however, 
  shoot 
  out 
  below, 
  and 
  

   afterward 
  yield 
  a 
  partial 
  crop, 
  seldom 
  exceeding 
  one-half 
  the 
  usual 
  

   quantity 
  of 
  grain" 
  (Gourgas 
  as 
  quoted 
  by 
  Harris). 
  The 
  worms 
  

   have 
  been 
  found 
  living 
  in 
  swellings, 
  sometimes 
  from 
  six 
  to 
  ten 
  in 
  a 
  

   tumor 
  situated 
  between 
  the 
  second 
  and 
  third 
  joints, 
  or 
  immediately 
  

   above 
  the 
  lower 
  joint 
  in 
  the 
  sheathing-base 
  of 
  the 
  leaf, 
  or 
  in 
  the 
  joint 
  

   itself. 
  In 
  November, 
  in 
  the 
  New 
  England 
  States, 
  the 
  fully-fed 
  larvse 
  as 
  

   a 
  rule 
  (many 
  do 
  not 
  until 
  the 
  spring) 
  change 
  to 
  a 
  chrysalis 
  or 
  pupa 
  

   within 
  the 
  tumor, 
  and 
  in 
  this 
  state 
  spend 
  the 
  winter 
  in 
  the 
  straw 
  or 
  

   stubble 
  or 
  even 
  in 
  some 
  cases 
  in 
  the 
  harvested 
  grain. 
  In 
  Virginia, 
  the 
  

   larva 
  passes 
  into 
  the 
  pupa 
  state 
  in 
  February 
  and 
  March. 
  From 
  early 
  in 
  

   May 
  until 
  early 
  in 
  July, 
  but 
  mostly 
  in 
  New 
  York 
  in 
  June, 
  the 
  four- 
  

   winged 
  flies 
  issue 
  from 
  the 
  galls, 
  the 
  males 
  first 
  appearing, 
  and 
  about 
  

   the 
  10th 
  of 
  June, 
  in 
  Canada, 
  the 
  females 
  deposit 
  their 
  eggs 
  in 
  the 
  stalks 
  

   of 
  the 
  young, 
  healthy 
  wheat. 
  The 
  larvae 
  hatch 
  in 
  a 
  few 
  days, 
  and 
  by 
  

   the 
  first 
  week 
  of 
  July 
  the 
  young 
  are 
  nearly 
  one-half 
  grown. 
  By 
  the 
  

   first 
  of 
  September 
  the 
  galls 
  become 
  hard 
  and 
  the 
  worms 
  fully 
  grown. 
  

  

  I 
  have 
  endeavored 
  to 
  represent 
  on 
  the 
  accompanying 
  map 
  the 
  area 
  

   of 
  distribution 
  of 
  the 
  joint-worm, 
  but 
  the 
  area 
  is 
  probably 
  too 
  restricted. 
  

   No 
  facts 
  are, 
  however, 
  at 
  hand 
  showing 
  that 
  it 
  has 
  occurred 
  west 
  of 
  

   longitude 
  82° 
  or 
  south 
  of 
  latitude 
  36°, 
  with 
  the 
  exception 
  that 
  a 
  "joint- 
  

   worm 
  " 
  is 
  reported 
  in 
  the 
  Monthly 
  Eeports 
  of 
  the 
  Agricultural 
  Depart- 
  

   ment 
  as 
  having 
  injured 
  wheat 
  in 
  Kansas, 
  but 
  the 
  species 
  referred 
  to 
  has 
  

   not, 
  so 
  far 
  as 
  I 
  am 
  aware, 
  been 
  referred 
  to 
  a 
  competent 
  botanist. 
  I 
  should 
  

   be 
  greatly 
  obliged 
  for 
  specimens 
  of 
  this 
  or 
  any 
  "joint- 
  worm" 
  from 
  any 
  

   part 
  of 
  the 
  country. 
  

  

  The 
  joint- 
  worm 
  of 
  late 
  years 
  has 
  been, 
  so 
  far 
  as 
  reports 
  go, 
  much 
  less 
  

   abundant 
  than 
  between 
  the 
  years 
  1825 
  and 
  1860, 
  and 
  it 
  is 
  to 
  be 
  hoped 
  

   that 
  it 
  will 
  not 
  again 
  be 
  so 
  prevalent. 
  In 
  former 
  years 
  the 
  losses 
  in 
  

   Virginia 
  amounted 
  to 
  over 
  a 
  third 
  of 
  the 
  entire 
  wheat-crop, 
  while 
  some 
  

   crops 
  in 
  that 
  State 
  were 
  not 
  thought 
  to 
  be 
  worth 
  cutting. 
  It 
  was 
  par- 
  

   ticularly 
  abundant 
  on 
  rye, 
  barley, 
  and 
  oats 
  in 
  the 
  New 
  England 
  States 
  

   and 
  Canada, 
  while 
  in 
  New 
  York 
  it 
  was 
  known 
  to 
  destroy 
  one-half 
  the 
  

   barley-crop. 
  Dr. 
  Fitch 
  has 
  described 
  several 
  so-called 
  species, 
  allied 
  to 
  

   Isosoma 
  hordei, 
  and 
  he 
  supposed 
  that 
  they 
  were 
  restricted 
  to 
  different 
  

   species 
  of 
  cereals. 
  Mr. 
  Walsh, 
  however, 
  has 
  endeavored 
  to 
  show, 
  with 
  

   good 
  reason, 
  we 
  think, 
  that 
  they 
  were 
  simply 
  varieties 
  of 
  I. 
  hordei, 
  and 
  

   that 
  this 
  well 
  known 
  species 
  feeds 
  upon 
  all 
  the 
  small 
  grains 
  as 
  well 
  as 
  

   wheat. 
  

  

  Either 
  two 
  or 
  three 
  specimens 
  of 
  ichneumon 
  or 
  chalcis 
  flies, 
  belonging 
  

   to 
  the 
  same 
  family 
  {Chalcididce) 
  of 
  hymenopterous 
  insects 
  as 
  the 
  joint- 
  

   worm 
  itself, 
  iDiey 
  upon 
  the 
  larva, 
  and 
  probably 
  tend 
  to 
  reduce 
  its 
  num- 
  

   bers. 
  Harris 
  states 
  that 
  the 
  larvse 
  of 
  a 
  species 
  of 
  Torynms, 
  one 
  of 
  these 
  

   chalcid 
  flies, 
  destroy 
  the 
  joint- 
  worm. 
  A 
  species 
  of 
  Torymus 
  {T. 
  Jiarrisii 
  

   Fitch), 
  perhaps 
  the 
  adult 
  of 
  the 
  larval 
  Torymus 
  described 
  by 
  Harris, 
  and 
  

   a 
  species 
  of 
  Pleromalus, 
  also 
  prey 
  upon 
  it. 
  

  

  Larva 
  : 
  The 
  joiut-worm 
  is 
  described 
  by 
  Harris, 
  from 
  specimens 
  received 
  from 
  Vir- 
  

   ginia, 
  as 
  a 
  round, 
  cylindrical, 
  footless, 
  maggot-like 
  worm, 
  varying 
  from 
  oue-teutb 
  to 
  

   three-twentieths 
  of 
  an 
  inch 
  in 
  length. 
  It 
  is 
  pale 
  yellowish 
  and 
  without 
  hairs. 
  The 
  

   head 
  is 
  round 
  and 
  partly 
  retractile, 
  with 
  a 
  distinct 
  pair 
  of 
  jaws, 
  and 
  can 
  be 
  distin- 
  

   guished 
  from 
  the 
  larvas 
  of 
  the 
  diptenous 
  gall-flies 
  by 
  not 
  having 
  the 
  usual 
  V-shai^ed 
  

   organs 
  on 
  the 
  segment 
  succeeding 
  the 
  head. 
  

  

  Adult 
  : 
  The 
  imago 
  or 
  adult 
  fly 
  is 
  a 
  four- 
  winged, 
  hymenopterous 
  insect, 
  a 
  member 
  of 
  

   the 
  family 
  Chalcididw, 
  most 
  of 
  which 
  are 
  insect-parasites. 
  It 
  is 
  jet 
  black, 
  and 
  the 
  

   thighs, 
  shanks 
  (tibipe), 
  and 
  claw-joints 
  of 
  the 
  feet 
  are 
  blackish, 
  while 
  the 
  knees 
  and 
  

   other 
  joints 
  of 
  the 
  feet 
  (tarsi) 
  are 
  pale 
  yellow; 
  sometimes 
  the 
  legs 
  are 
  entirely 
  yellow. 
  

   The 
  females 
  are 
  0.13 
  inch 
  in 
  leugth, 
  wliile 
  the 
  males 
  are 
  smaller, 
  have 
  a 
  club-shaped 
  

   abdomen, 
  and 
  the 
  joints 
  of 
  the 
  antennas 
  are 
  surrounded 
  by 
  a 
  verticil 
  of 
  hairs. 
  

  

  