﻿30 
  A. 
  K. 
  MORDVILKO. 
  

  

  49 
  (50). 
  Cornicles 
  longer 
  than 
  Cauda 
  ; 
  body 
  of 
  apterous 
  viviparous 
  22 
  dull 
  green 
  

  

  or 
  whitish 
  green, 
  but 
  front 
  part 
  of 
  head 
  generally 
  dark 
  tawny, 
  and 
  

   brown 
  tranverse 
  lines 
  on 
  8th 
  (and 
  sometimes 
  7th) 
  abdominal 
  segment. 
  

   In 
  partly 
  curled 
  upper 
  leaves 
  of 
  Panicum 
  crus-galli, 
  Sorghum, 
  Hordeum. 
  

   etc., 
  but 
  sometimes 
  on 
  the 
  ears 
  and 
  external 
  surface 
  of 
  leaves. 
  . 
  

  

  A. 
  maidis, 
  Fitch 
  

   (= 
  avenae, 
  Kalt., 
  nee 
  F., 
  nee 
  Mordv.). 
  

  

  50 
  (49). 
  Cornicles 
  not 
  longer 
  than 
  Cauda 
  ; 
  body 
  brownish, 
  covered 
  in 
  places 
  with 
  

  

  white 
  dust, 
  owing 
  to 
  which 
  the 
  living 
  Aphids 
  have 
  a 
  variegated 
  appear- 
  

   ance. 
  On 
  leaves 
  of 
  Arundo 
  donax 
  ; 
  S. 
  Europe 
  (Italj 
  7 
  , 
  Transcaucasia) 
  

  

  A. 
  donacis, 
  Pass. 
  

  

  51 
  (38). 
  Cornicles 
  distinctly 
  constricted 
  before 
  the 
  operculum 
  ; 
  operculum 
  broad, 
  

  

  as 
  wide 
  as 
  or 
  wider 
  than 
  the 
  middle 
  of 
  the 
  cornicle 
  

  

  Genus 
  Siphonaphis, 
  v. 
  d. 
  Goot. 
  

  

  Body 
  of 
  apterous 
  viviparous 
  22 
  green 
  with 
  reddish 
  brown 
  spots 
  

   at 
  the 
  base 
  of 
  cornicles, 
  broadly 
  ovate, 
  its 
  width 
  slightly 
  more 
  

   than 
  half 
  the 
  length. 
  On 
  leaves 
  and 
  flowering 
  parts 
  of 
  various 
  

   Graminaceae 
  ; 
  Palaearctic 
  (in 
  connection 
  with 
  distribution 
  of 
  Primus 
  

   padus) 
  and 
  N. 
  America 
  

  

  exules 
  of 
  S. 
  padi, 
  L. 
  (= 
  avenae, 
  Mordv., 
  Perg., 
  

   Davis, 
  Theo., 
  Patch., 
  etc., 
  nee 
  Fabr.). 
  

  

  Two 
  subspecies 
  may 
  be 
  recognised 
  in 
  the 
  case 
  of 
  the 
  exules. 
  

  

  *(**). 
  Spur 
  of 
  last 
  joint 
  of 
  antennae 
  ly-l£ 
  times 
  as 
  long 
  as 
  the 
  

   3rd 
  joint 
  (in 
  alate 
  sexuparae 
  almost 
  equal 
  to 
  it 
  or 
  slightly 
  longer 
  

   or 
  shorter). 
  Palaearctic 
  .. 
  .. 
  .. 
  S. 
  padi 
  padi, 
  L. 
  

  

  **(*). 
  Spur 
  of 
  last 
  joint 
  of 
  antennae 
  about 
  If 
  times 
  as 
  long 
  as 
  

  

  the 
  3rd 
  joint 
  (in 
  alate 
  sexuparae 
  1^-1 
  f 
  times). 
  N. 
  America 
  . 
  . 
  

  

  S. 
  padi 
  americana, 
  subsp. 
  n. 
  (— 
  Siphocoryne 
  avenae, 
  Perg., 
  

  

  and 
  other 
  American 
  authors).* 
  

  

  Also 
  in 
  the 
  fundatrigeniae 
  : 
  — 
  

  

  *(**). 
  Spur 
  of 
  6th 
  joint 
  of 
  antennae 
  shorter 
  than 
  3rd 
  joint, 
  seldom 
  

   almost 
  equal 
  to 
  it 
  (more 
  often 
  in 
  alate 
  viviparous 
  $2) 
  

  

  S. 
  padi 
  padi, 
  L. 
  

  

  **(*). 
  Spur 
  of 
  6th 
  joint 
  of 
  antennae 
  longer 
  than 
  3rd 
  joint 
  

  

  S. 
  padi 
  americana, 
  subsp. 
  n. 
  

  

  52 
  (29). 
  Antennae 
  5-jointed, 
  short, 
  about 
  half 
  the 
  length 
  of 
  body, 
  at 
  least 
  in 
  

  

  apterous 
  viviparous 
  22. 
  

  

  53 
  (54). 
  Cornicles 
  very 
  short, 
  shorter 
  than 
  cauda, 
  almost 
  cylindrical, 
  narrowing 
  

  

  slightly 
  towards 
  the 
  operculum, 
  which 
  is 
  slightly 
  broader 
  than 
  the 
  

   penultimate 
  portion 
  of 
  cornicle 
  ; 
  cauda 
  elongate, 
  thicker 
  in 
  the 
  middle 
  

   than 
  the 
  middle 
  portion 
  of 
  cornicles 
  ; 
  of 
  the 
  marginal 
  tubercles 
  only 
  

   those 
  on 
  prothorax 
  and 
  7th 
  abdominal 
  segment 
  fairly 
  distinct 
  

  

  Genus 
  Geoktapia, 
  n. 
  

  

  * 
  If 
  " 
  Siphocoryne" 
  splendens, 
  Theo., 
  found 
  in 
  Egypt 
  (Gizeh, 
  18.ii.08) 
  on 
  whe.it, 
  is 
  near 
  to 
  

   Aphis 
  padi, 
  L., 
  owing 
  to 
  the 
  structure 
  of 
  the 
  cornicles 
  and 
  other 
  characters 
  it 
  is 
  in 
  any 
  case 
  

   distinguished 
  by 
  having 
  fairly 
  long 
  hairs 
  on 
  the 
  antennae 
  and 
  legs 
  (in 
  A. 
  padi 
  the 
  hairs 
  on 
  the 
  

   3rd 
  joint 
  of 
  the 
  antennae 
  hardly 
  exceed 
  half 
  the 
  diameter 
  of 
  the 
  joint, 
  whereas 
  in 
  " 
  Siphocoryne 
  " 
  

   splendens, 
  to 
  judge 
  by 
  Theobald's 
  illustration, 
  they 
  are 
  at 
  least 
  equal 
  to 
  the 
  diameter; 
  besides 
  

   this, 
  the 
  cornicles 
  in 
  A. 
  padi 
  are 
  decidedly 
  shorter 
  than 
  the 
  3rd 
  joint 
  of 
  the 
  antennae, 
  while 
  in 
  

   S. 
  splendens 
  they 
  are 
  longer 
  (cf. 
  F. 
  V. 
  Theobald, 
  1915). 
  

  

  