﻿KEYS 
  FOR 
  THE 
  DETERMINATION 
  OF 
  APHIDS. 
  39 
  

  

  9 
  (10) 
  Third 
  joint 
  of 
  antennae 
  almost 
  equal 
  to 
  5th, 
  others 
  considerably 
  shorter 
  

   than 
  they 
  ; 
  four 
  longitudinal 
  rows 
  of 
  grouped 
  glands, 
  better 
  pronounced 
  

   on 
  the 
  hind 
  part 
  of 
  abdomen.* 
  On 
  roots 
  of 
  Panicum 
  proliferum 
  and 
  

   P. 
  glabrum 
  ; 
  N. 
  America 
  . 
  . 
  . 
  . 
  . 
  . 
  Rhizobius 
  spicatus, 
  Forbes. 
  

  

  10 
  (9). 
  Fifth 
  joint 
  of 
  antennae 
  longer 
  than 
  3rd. 
  

  

  11 
  (12). 
  Third 
  joint 
  of 
  antennae 
  distinctly 
  longer 
  than 
  2nd 
  and 
  4th, 
  although 
  

  

  shorter 
  than 
  the 
  others, 
  only 
  slightly 
  shorter 
  than 
  1st 
  joint 
  or 
  subequal 
  

   to 
  it 
  ; 
  tibiae 
  somewhat 
  longer 
  than 
  femora 
  ; 
  hairs 
  on 
  body 
  and 
  

   extremities 
  not 
  noticeable 
  

  

  Tychea 
  eragrostidis, 
  Pass., 
  Buckt.t 
  

   (= 
  Tychea 
  brevicomis, 
  Forbes). 
  

  

  12 
  (11). 
  Third 
  joint 
  of 
  antennae 
  somewhat 
  shorter 
  than 
  2nd 
  and 
  even 
  the 
  1st, 
  

  

  but 
  sometimes 
  almost 
  equal 
  to 
  1st 
  ; 
  4th 
  joint 
  considerably 
  shorter 
  

   than 
  the 
  rest, 
  almost 
  half 
  of 
  the 
  2nd 
  ; 
  tibiae 
  somewhat 
  shorter 
  than 
  

   femora 
  ; 
  only 
  the 
  marginal 
  groups 
  of 
  glands 
  clearly 
  visible, 
  the 
  pleural 
  

   ones 
  may 
  also 
  be 
  partly 
  perceptible 
  {Pemphigella 
  ? 
  p. 
  19, 
  footnote) 
  

  

  Tychea 
  sylvestrii, 
  sp. 
  n.\ 
  

  

  13 
  (4). 
  Third 
  joint 
  of 
  antennae 
  longer 
  than 
  the 
  others 
  ; 
  body 
  whitish 
  yellow, 
  

  

  with 
  an 
  admixture 
  of 
  meat-red 
  or 
  pink. 
  In 
  ants' 
  nests 
  and 
  on 
  roots 
  of 
  

   Avena 
  pratensis 
  ; 
  South 
  England, 
  Belgium 
  . 
  . 
  Endeis 
  carnosa, 
  Buckt. 
  

  

  14 
  (1). 
  Antennae 
  6-jointed 
  in 
  apterous 
  viviparous 
  ?$ 
  from 
  roots. 
  

  

  15 
  (16). 
  Antennae 
  short, 
  3rd 
  joint 
  the 
  shortest, 
  not 
  more 
  than 
  half 
  of 
  2nd 
  ; 
  last 
  

  

  three 
  joints 
  almost 
  equal 
  to 
  each 
  other. 
  On 
  roots 
  of 
  Poa 
  annua 
  ; 
  N. 
  

   America 
  . 
  . 
  . 
  . 
  . 
  . 
  . 
  . 
  . 
  . 
  Rhizobius 
  poae, 
  Thomas. 
  

  

  16 
  (15). 
  Antennae 
  one-quarter 
  the 
  length 
  of 
  body 
  ; 
  3rd 
  joint 
  somewhat 
  longer 
  

  

  than 
  the 
  others, 
  but 
  shorter 
  than 
  1st 
  and 
  2nd 
  together 
  ; 
  4th 
  joint 
  

   somewhat 
  shorter 
  than 
  5th, 
  and 
  the 
  latter 
  almost 
  equal 
  to 
  basal 
  portion 
  

   of 
  6th 
  ; 
  colour 
  dirty 
  white 
  ; 
  on 
  dorsal 
  surface 
  six 
  longitudinal 
  rows 
  of 
  

   grouped 
  glands 
  ; 
  length 
  of 
  body 
  2-2 
  mm. 
  On 
  roots 
  of 
  Graminaceae 
  

   and 
  possibly 
  other 
  plants 
  ; 
  N. 
  America 
  

  

  Trama 
  " 
  erigeronensis, 
  Thomas. 
  

  

  * 
  The 
  disposition 
  of 
  the 
  glands 
  (from 
  above 
  only 
  four 
  longitudinal 
  rows 
  are 
  visible, 
  and 
  not 
  

   all 
  six) 
  suggests 
  that 
  this 
  species 
  may 
  belong 
  to 
  the 
  tribe 
  Schizoneurea. 
  The 
  settlement 
  of 
  

   this 
  question 
  is 
  impossible 
  without 
  a 
  more 
  detailed 
  description 
  of 
  the 
  groups 
  of 
  glands. 
  

  

  t 
  It 
  may 
  be 
  that 
  the 
  N. 
  American 
  species 
  (Colorado) 
  from 
  ant 
  nests, 
  Tychea 
  lasii, 
  Ckll., 
  and 
  

   crassa, 
  Ckll. 
  (Psyche, 
  1903) 
  are 
  closely 
  related 
  to 
  this 
  species. 
  

  

  I 
  T. 
  pallidula, 
  Cockerell 
  (Psyche, 
  1903) 
  from 
  Kf. 
  America, 
  in 
  which 
  the 
  3rd 
  joint 
  is 
  longer 
  than 
  

   1st, 
  is 
  distinct 
  from 
  this 
  species. 
  

  

  