﻿290 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  Pemphigus 
  rhois 
  (Fitch). 
  

  

  The 
  Stimac-Gall 
  Aphis. 
  

  

  (Ord. 
  Hemiptera 
  : 
  Subord. 
  Homoptera: 
  Fam. 
  Aphidid^.) 
  

  

  Fitch: 
  in 
  Month. 
  Journ. 
  N. 
  Y. 
  St. 
  Agricul. 
  Soc. 
  for 
  Aug., 
  1866, 
  p. 
  73 
  

  

  (described, 
  as 
  Byrsocrypta 
  rhois 
  with 
  remarks). 
  

   Walsh: 
  in 
  Proc. 
  Entomolog. 
  Soc. 
  Phil., 
  vi, 
  1866, 
  p. 
  281 
  (referred 
  to 
  

  

  Melaphis). 
  

   Packard: 
  Guide 
  Study 
  Ins., 
  1869, 
  p. 
  524, 
  fig. 
  523 
  (brief 
  mention). 
  

   Walsh-Riley 
  : 
  in 
  Amer. 
  EntomoL, 
  i, 
  1869, 
  p. 
  jo8, 
  fig. 
  89 
  (brief 
  mention, 
  

  

  in 
  Illinois 
  and 
  New 
  York). 
  

   Thomas: 
  8th 
  Rept. 
  Ins. 
  111., 
  1879, 
  PP- 
  ^^52-153, 
  fig- 
  28 
  (brief 
  mention). 
  

   LiNTNER 
  : 
  3rd 
  Rept. 
  Ins. 
  N. 
  Y,, 
  1887, 
  p. 
  142 
  (from 
  Schenectady) 
  ; 
  in 
  

  

  Country 
  Gent., 
  lix, 
  1894, 
  p. 
  686 
  (brief 
  account); 
  loth 
  Rept. 
  

  

  Ins. 
  N. 
  Y., 
  1895, 
  p. 
  503 
  (abstract 
  of 
  preceding, 
  all 
  as 
  Melaphis). 
  

   Oestlund 
  : 
  Bull. 
  4 
  Geolog. 
  and 
  Nat. 
  Hist. 
  Surv. 
  Minn., 
  1887, 
  p. 
  23 
  

  

  (bibliography, 
  description, 
  remarks). 
  

   Smith 
  : 
  Cat. 
  Ins. 
  N. 
  J., 
  1890, 
  p. 
  451 
  (listed). 
  

   RiLEY-HowARD 
  : 
  ill 
  Inscct 
  Life, 
  V, 
  1892, 
  p. 
  145 
  (tannin 
  in 
  gall). 
  

  

  This 
  insect 
  is 
  rarely 
  seen, 
  except 
  by 
  those 
  curious 
  enough 
  to 
  cut 
  open 
  

   one 
  of 
  the 
  galls 
  that 
  it 
  forms 
  on 
  the 
  leaves 
  of 
  sumac. 
  If 
  the 
  examination 
  

   be 
  made 
  in 
  September, 
  it 
  will 
  be 
  found 
  tightly 
  packed 
  with 
  particles 
  of 
  

   white 
  flocculent 
  matter 
  which 
  are 
  the 
  cast 
  skins 
  (exuvise) 
  of 
  the 
  lice 
  at 
  

   their 
  successive 
  moltings, 
  hundreds 
  of 
  yellow-green 
  wingless 
  aphides, 
  

   with 
  wing-pads 
  upon 
  their 
  sides 
  (the 
  pupal 
  stage 
  of 
  the 
  insect), 
  and 
  a 
  

   smaller 
  number 
  of 
  matured 
  winged 
  forms. 
  A 
  little 
  later 
  all 
  will 
  have 
  be- 
  

   come 
  winged. 
  

  

  This 
  insect 
  was 
  referred 
  to 
  the 
  genus 
  Byi^socrypta 
  by 
  its 
  describer, 
  Dr. 
  

   Fitch, 
  in 
  1866. 
  Shortly 
  thereafter 
  Mr. 
  Walsh 
  made 
  it 
  the 
  type 
  for 
  the 
  

   new 
  genus 
  Melaphis^ 
  but 
  upon 
  insufficient 
  grounds, 
  according 
  to 
  Mr. 
  

   Oestlund, 
  who 
  has 
  recently 
  placed 
  it 
  in 
  the 
  genus 
  Pemphigus. 
  

  

  Description 
  of 
  the 
  Gall 
  and 
  Immature 
  Aphides 
  

   The 
  galls 
  have 
  been 
  described 
  by 
  Dr. 
  Fitch 
  as 
  follows 
  : 
  

  

  Resembling 
  litde 
  round 
  balls 
  of 
  different 
  sizes, 
  the 
  largest 
  measuring 
  

   an 
  inch 
  in 
  diameter, 
  their 
  surface 
  uneven 
  and 
  slightly 
  knobby 
  in 
  places, 
  

   and 
  covered 
  with 
  fine 
  erect 
  white 
  hairs; 
  their 
  color 
  pale 
  buff-yellow 
  or 
  

   greenish-yellow, 
  and 
  on 
  the 
  side 
  exposed 
  to 
  the 
  sun 
  bright 
  crimson-red. 
  

   Attached 
  to 
  the 
  leaf 
  by 
  a 
  narrow 
  neck, 
  opposite 
  which, 
  on 
  the 
  upper 
  side 
  

   of 
  the 
  leaf, 
  is 
  a 
  thickened 
  wart-like 
  elevation, 
  or 
  sometimes 
  higher 
  con- 
  

   ical 
  protuberance, 
  which 
  is 
  also 
  covered 
  with 
  erect 
  white 
  hairs 
  ; 
  and 
  the 
  

   leaf 
  itself 
  is 
  partly 
  withered, 
  and 
  turned 
  red 
  or 
  yellow. 
  Cavity 
  inside 
  

   large; 
  in 
  the 
  smaller 
  galls 
  filled 
  with 
  small, 
  oval, 
  pale 
  dull 
  yellow 
  lice 
  of 
  

   different 
  sizes, 
  their 
  eyes 
  black, 
  their 
  feet 
  and 
  antennce 
  white, 
  the 
  larger 
  

   ones 
  measuring 
  0.03 
  in 
  length, 
  and 
  some 
  of 
  these 
  larger 
  ones 
  thinly 
  

  

  