﻿XVII 
  

  

  tibia 
  ends 
  in 
  a 
  cup-like 
  expansion 
  receiving 
  the 
  tarsus, 
  which 
  in 
  

   articulated 
  to 
  the 
  former 
  by 
  what 
  appears 
  to 
  be 
  a 
  rudimentary 
  first 
  

   joint. 
  The 
  tarsus 
  is 
  serrate 
  and 
  ringed, 
  bearing 
  a 
  few 
  hairs 
  in 
  po- 
  

   sitions 
  shown 
  in 
  the 
  drawing. 
  A 
  small 
  trochanter 
  is 
  present 
  in 
  its 
  

   usual 
  position. 
  (Plate 
  1, 
  Fig. 
  2.) 
  

  

  The 
  Apterous 
  Female. 
  

  

  "The 
  apterous 
  female 
  is 
  not 
  fixed, 
  but 
  eucJosed 
  in 
  a 
  woolly 
  mass 
  which 
  ad- 
  

   heres 
  to 
  the 
  bark. 
  The 
  legs 
  and 
  antenna' 
  are 
  persistent, 
  comparatively 
  

   small. 
  The 
  antennae 
  are 
  three-jointed, 
  and 
  the 
  tarsi 
  one-jointed, 
  terminated 
  

   by 
  two 
  ungues. 
  The 
  body 
  is 
  elongated, 
  pyriform 
  during 
  egg-Jaying; 
  con- 
  

   tracted 
  to 
  a 
  globular 
  or 
  flattened 
  foi-m 
  afterward 
  or 
  in 
  winter.*' 
  — 
  Osborn. 
  

  

  My 
  observations 
  lead 
  me 
  to 
  think 
  that 
  the 
  apterous 
  female 
  is 
  often, 
  

   though 
  not 
  alw^ays, 
  free 
  from 
  the 
  bark 
  during 
  the 
  winter 
  months. 
  

   When 
  spring 
  opens 
  the 
  tube 
  is 
  inserted 
  and 
  the 
  insect 
  remains 
  fixed 
  

   for 
  the 
  remainder 
  of 
  its 
  life. 
  The 
  long 
  sucking 
  tube 
  found 
  in 
  this 
  

   form 
  is 
  similar 
  to 
  that 
  of 
  the 
  larva 
  before 
  described, 
  but 
  the 
  sheath 
  

   difiPers 
  slightly. 
  The 
  sheath 
  of 
  the 
  apterous 
  female 
  lies 
  in 
  a 
  fossa 
  

   formed 
  by 
  the 
  coxa 
  and 
  their 
  supporting 
  sclerites. 
  No 
  differences 
  of 
  

   importance 
  were 
  discovered 
  in 
  the 
  three 
  pairs 
  of 
  legs: 
  all 
  are 
  very 
  

   short, 
  so 
  short 
  that 
  the 
  insect 
  can 
  not 
  right 
  itself 
  wdien 
  placed 
  upon 
  its 
  

   back. 
  The 
  thickness 
  of 
  the 
  femur 
  is 
  about 
  two 
  thirds 
  its 
  length, 
  the 
  

   tibia 
  is 
  as 
  long 
  as 
  the 
  femur 
  but 
  more 
  slender, 
  the 
  tarsus 
  about 
  one 
  

   half 
  the 
  length 
  of 
  the 
  tibia. 
  Both 
  tarsus 
  and 
  tibia 
  showed 
  a 
  few" 
  hairs, 
  

   such 
  as 
  were 
  observed 
  being 
  shown 
  in 
  the 
  drawing 
  (Plate 
  III, 
  Fig. 
  4 
  j 
  

   in 
  proper 
  position. 
  As 
  in 
  the 
  case 
  of 
  the 
  larval 
  tarsus, 
  but 
  one 
  ring 
  is 
  

   visible 
  on 
  the 
  tarsus 
  of 
  the 
  apterous 
  female, 
  and 
  that 
  one 
  so 
  situated 
  

   as 
  to 
  once 
  more 
  suggest 
  a 
  first 
  joint. 
  A 
  curious 
  notch 
  is 
  visible 
  just 
  

   at 
  the 
  base 
  of 
  the 
  two 
  claws. 
  

  

  Average 
  measurements 
  of 
  insect 
  before 
  egg-laying 
  period 
  were 
  

   0.51 
  mm. 
  X 
  0.345 
  mm.; 
  sucking 
  beak, 
  1.385 
  mm. 
  Measurements 
  dur- 
  

   ing 
  the 
  period 
  of 
  egg-laying 
  were: 
  width, 
  0.485 
  mm. 
  to 
  0.605 
  mm., 
  

   length, 
  0.52 
  mm. 
  to 
  0.71 
  mm., 
  averaging 
  0.55 
  mm. 
  X 
  0.60 
  mm. 
  

  

  The 
  ventral 
  surface 
  of 
  the 
  abdomen 
  shows 
  six 
  segments, 
  the 
  last 
  

   being 
  widest. 
  Color, 
  before 
  the 
  period 
  of 
  egg-laying, 
  brown 
  to 
  black 
  

   on 
  head 
  and 
  thorax, 
  abdomen 
  yellowish, 
  shading 
  to 
  brown 
  on 
  the 
  

   cephalic 
  segments. 
  The 
  •"spinnerets" 
  or 
  excretory 
  pores 
  are 
  disposed 
  

   with 
  regularity 
  on 
  the 
  abdomen, 
  a 
  double 
  row 
  down 
  the 
  back 
  and 
  a 
  

   single 
  row 
  on 
  each 
  side 
  of 
  the 
  body, 
  none 
  on 
  the 
  ventral 
  aspect. 
  On 
  

   the 
  thorax 
  the 
  arrangement 
  is 
  different, 
  the 
  groups 
  of 
  pores 
  being 
  

   on 
  both 
  ventral 
  and 
  dorsal 
  surfaces. 
  The 
  ventral 
  surface 
  of 
  the 
  

   caudal 
  third 
  of 
  the 
  thorax 
  is 
  free 
  from 
  pores. 
  These 
  pores, 
  from 
  

   which 
  the 
  woolly 
  excretion 
  so 
  often 
  mentioned 
  comes, 
  are 
  arranged 
  

   in 
  groups, 
  each 
  group 
  occupying 
  a 
  small 
  circular 
  elevation 
  or 
  

   papilla, 
  the 
  papilla^ 
  being 
  in 
  turn 
  gathered 
  into 
  groups 
  of 
  from 
  four 
  

   to 
  twenty. 
  From 
  this 
  form 
  of 
  the 
  pores, 
  the 
  inference 
  is 
  that 
  

   the 
  fibers 
  of 
  woolly 
  material 
  excreted 
  really 
  consist, 
  like 
  the 
  spider's 
  

   web, 
  of 
  numerous 
  fine 
  threads 
  which 
  cohere 
  into 
  one. 
  

  

  — 
  B 
  E. 
  

  

  