﻿XV 
  

  

  In 
  experiment 
  No. 
  -i 
  the 
  egg 
  was 
  found 
  still 
  adhering 
  to 
  the 
  abdo- 
  

   men 
  of 
  the 
  female 
  and 
  was 
  observed 
  not 
  to 
  be 
  hatched 
  at 
  10 
  a. 
  m. 
  

   May 
  5, 
  but 
  by 
  5 
  p- 
  m. 
  of 
  the 
  same 
  date 
  the 
  larva 
  had 
  emerged. 
  The 
  

   time 
  required 
  for 
  incubation, 
  therefore, 
  is 
  prol)ably 
  about 
  six 
  days, 
  

   though 
  it 
  will 
  vary 
  no 
  doubt 
  as 
  external 
  conditions 
  change. 
  I 
  was 
  

   unable 
  to 
  determine 
  the 
  number 
  of 
  eggs 
  deposited 
  by 
  an 
  apterous 
  

   female 
  in 
  the 
  course 
  of 
  the 
  season, 
  but 
  believe 
  it 
  to 
  be 
  nearer 
  sixty 
  

   than 
  five. 
  

  

  The 
  Larcd" 
  of 
  the 
  Winged 
  Form. 
  

  

  "The 
  larva' 
  wheu 
  first 
  hatched 
  are 
  oval 
  in 
  shape, 
  flattened, 
  yellowish, 
  or 
  

   light 
  brown. 
  Professor 
  Riley 
  in 
  his 
  mannscript 
  notes 
  says 
  'purple-red,' 
  but 
  1 
  

   have 
  not 
  been 
  able 
  to 
  detect 
  this 
  color. 
  The 
  antennte 
  are 
  three- 
  jointed; 
  the 
  

   first 
  joint 
  is 
  short 
  and 
  thick; 
  the 
  second 
  is 
  slightly 
  longer 
  and 
  not 
  so 
  

   thick; 
  the 
  third 
  is 
  three 
  times 
  as 
  long 
  as 
  the 
  first 
  and 
  half 
  as 
  thick, 
  set 
  with 
  

   a 
  few 
  stiff 
  hairs 
  at 
  the 
  apex, 
  one 
  being 
  two 
  thirds 
  the 
  length 
  of 
  the 
  joint: 
  also 
  

   a 
  few 
  lateral 
  hairs. 
  Near 
  the 
  end 
  of 
  this 
  joint 
  are 
  a 
  few 
  transverse 
  marks 
  or 
  

   ridges 
  extending 
  part 
  way 
  around. 
  

  

  •'The 
  month 
  parts 
  are 
  well 
  developed; 
  there 
  is 
  a 
  long 
  sucking 
  tube, 
  twice 
  

   the 
  length 
  of 
  the 
  body, 
  inclosed 
  in 
  a 
  sheath 
  extending 
  under 
  the 
  body 
  nearly 
  

   to 
  the 
  end 
  of 
  the 
  abdomen. 
  The 
  sheath 
  is 
  apparently 
  foi 
  r- 
  jointed, 
  sparsely 
  

   set 
  with 
  stiff 
  hairs, 
  mostly 
  at 
  the 
  apex; 
  'the 
  legs 
  are 
  of 
  moderate 
  length, 
  coxa 
  

   short 
  and 
  thick, 
  femur 
  and 
  tibia 
  equal; 
  tarsus 
  one-jointed, 
  half 
  the 
  length 
  of 
  

   the. 
  tibia, 
  ending 
  in 
  two 
  short 
  ungues 
  surrounded 
  bydigitula 
  (knobbed 
  hairs). 
  

   There 
  is 
  a 
  short 
  hair 
  or 
  seta 
  on 
  the 
  outer 
  angle 
  of 
  each 
  abdominal 
  segment. 
  

   Length, 
  0.38 
  mm.; 
  width, 
  0.19 
  mm.; 
  antenna-, 
  0.12 
  mm.; 
  legs, 
  0.15-0.18 
  mm. 
  

  

  "As 
  these 
  larvje 
  grow 
  they 
  become 
  darker 
  in 
  color, 
  assuming 
  a 
  deep 
  red- 
  

   brown, 
  and 
  finally 
  almost 
  black, 
  appearance, 
  while 
  the 
  woolly 
  substance 
  de- 
  

   velops 
  thickly 
  on 
  the 
  abdominal 
  segments 
  and 
  also 
  on 
  the 
  meso- 
  and 
  naeta- 
  

   thorax, 
  entirely 
  hiding 
  the 
  insect, 
  which 
  thus 
  appears 
  like 
  a 
  ball 
  of 
  white 
  

   down. 
  The 
  substance 
  develops 
  from 
  gland- 
  like 
  surfaces 
  arranged 
  sub-dorsally 
  

   on 
  each 
  segment, 
  the 
  abdominal 
  segments 
  having 
  also 
  a 
  lateral 
  row 
  of 
  smaller 
  

   surfaces 
  performing 
  the 
  same 
  office." 
  — 
  Osborn. 
  

  

  All 
  newly 
  hatched 
  larvae 
  observed 
  at 
  Urbana 
  were 
  yellow; 
  antenn* 
  

   three- 
  jointed, 
  thick 
  and 
  fleshy; 
  first 
  and 
  second 
  joints 
  about 
  the 
  same 
  

   size, 
  the 
  three 
  diameters 
  of 
  each 
  apparently 
  equal, 
  the 
  width, 
  how- 
  

   ever, 
  in 
  rare 
  cases, 
  exceeding 
  the 
  length, 
  also 
  the 
  second 
  joint 
  some- 
  

   times 
  exceeding 
  the 
  first 
  in 
  all 
  dimensions. 
  The 
  third 
  joint 
  appears 
  

   as 
  described 
  by 
  Professor 
  Osborn, 
  except 
  that 
  the 
  edge 
  is 
  usually 
  

   irregularly 
  serrate, 
  and 
  the 
  joint 
  shows 
  throughout 
  its 
  extent 
  the 
  

   rings 
  he 
  mentions 
  as 
  being 
  near 
  its 
  distal 
  extremity. 
  The 
  distal 
  ex- 
  

   tremity 
  bears 
  four 
  hairs, 
  one 
  long 
  and 
  the 
  others 
  about 
  half 
  its 
  length. 
  

   Two 
  or 
  three 
  other 
  very 
  short 
  hairs 
  were 
  observed 
  along 
  the 
  edges 
  of 
  

   this 
  segment. 
  At 
  the 
  posterior 
  distal 
  angle 
  of 
  the 
  second 
  segment 
  

   another 
  short 
  hair 
  is 
  located, 
  while 
  four 
  others 
  are 
  visible 
  along 
  the 
  

   cephalic 
  margin 
  of 
  the 
  head, 
  and 
  still 
  another 
  at 
  the 
  latero-cephalic 
  

   angle. 
  The 
  eye 
  consists 
  of 
  three 
  ocelli. 
  The 
  hairs 
  on 
  the 
  margin 
  of 
  

   each 
  abdominal 
  segment 
  are 
  the 
  same 
  in 
  my 
  specimens 
  as 
  in 
  Professor 
  

   Osborn's. 
  I 
  notice, 
  however, 
  that 
  the 
  two 
  hairs 
  at 
  the 
  caudal 
  ex- 
  

   tremity 
  surpass 
  the 
  others 
  in 
  length 
  and 
  thickness. 
  (Plate 
  II, 
  Figs. 
  

   1 
  and 
  'i. 
  ) 
  

  

  The 
  sucking 
  tube 
  is 
  usually 
  bent 
  on 
  itself, 
  the 
  extnnne 
  end 
  only 
  

   being 
  inserted 
  .into 
  the 
  sheath. 
  The 
  tube 
  is 
  composed 
  of 
  three 
  fila- 
  

   ments. 
  The 
  tarsus 
  appears 
  to 
  be 
  free 
  from 
  rings 
  with 
  the 
  exception 
  

  

  