﻿406 
  

  

  BoRNER 
  (C). 
  Blattlausstudien. 
  [Studies 
  of 
  Plant 
  Lica. 
  ]~Abhand. 
  

   Naturwiss. 
  Ver., 
  Bremen, 
  xxiii, 
  pt. 
  1, 
  1914, 
  pp. 
  164-184, 
  4 
  figs. 
  

  

  After 
  giving 
  a 
  summary 
  of 
  the 
  known 
  facts 
  as 
  to 
  the 
  migration 
  

   from 
  one 
  host 
  to 
  another 
  of 
  57 
  species 
  of 
  Aphids, 
  the 
  author 
  records 
  the 
  

   habits 
  of 
  several 
  species 
  of 
  which 
  he 
  has 
  himself 
  worked 
  out 
  the 
  life- 
  

   history 
  and 
  studied 
  the 
  migrations. 
  

  

  Aphis 
  (Brachycaudus) 
  pruni, 
  Koch, 
  was 
  observed 
  in 
  the 
  neighbour- 
  

   hood 
  of 
  Metz 
  ; 
  in 
  the 
  spring 
  they 
  were 
  found 
  in 
  large 
  numbers 
  on 
  

   Primus 
  domestica 
  and 
  P. 
  institia, 
  more 
  rarely 
  on 
  P. 
  spinosa, 
  and 
  

   they 
  cause 
  the 
  leaves 
  of 
  these 
  trees 
  to 
  curl 
  up 
  and 
  fall 
  off. 
  The 
  

   individuals 
  found 
  on 
  Primus 
  in 
  the 
  spring 
  are 
  the 
  wingless 
  females 
  

   (stem-mothers) 
  ; 
  they 
  give 
  rise 
  parthenogenetically 
  to 
  winged 
  indi- 
  

   viduals 
  which 
  leave 
  the 
  original 
  host-plant 
  and 
  fly 
  to 
  various 
  wild 
  

   plants, 
  in 
  May 
  and 
  June. 
  In 
  August, 
  winged 
  individuals 
  appear 
  in 
  

   large 
  numbers 
  ; 
  they 
  are 
  produced 
  parthenogenetically 
  and 
  consist 
  

   of 
  both 
  males 
  and 
  females 
  ; 
  they 
  return 
  to 
  Prunus, 
  on 
  which 
  the 
  

   eggs 
  are 
  laid, 
  before 
  winter 
  sets 
  in. 
  

  

  Aphis 
  piri, 
  Boyer, 
  was 
  common 
  in 
  the 
  neighbourhood 
  of 
  Metz 
  in 
  

   the 
  summer 
  of 
  1913. 
  From 
  May 
  onwards, 
  wingless 
  females 
  were 
  

   found 
  on 
  the 
  underside 
  of 
  the 
  leaves 
  of 
  apple-trees 
  ; 
  the 
  first 
  genera- 
  

   tion 
  to 
  which 
  these 
  give 
  rise 
  are 
  wingless 
  individuals 
  ; 
  the 
  individuals 
  

   of 
  the 
  second 
  generation 
  are 
  winged 
  ; 
  these 
  leave 
  the 
  apple-trees 
  

   in 
  July 
  and 
  were 
  found 
  in 
  August 
  on 
  the 
  roots 
  of 
  Rumex 
  (dock). 
  

   Winged 
  males 
  and 
  females 
  were 
  produced 
  on 
  this 
  host-plant 
  ; 
  the 
  

   latter 
  migrated 
  to 
  the 
  apple, 
  where 
  another 
  generation 
  of 
  females 
  was 
  

   produced 
  ; 
  these 
  were 
  joined 
  by 
  the 
  mature 
  males 
  and 
  fertilised, 
  the 
  

   eggs 
  being 
  laid 
  in 
  the 
  buds 
  and 
  on 
  the 
  cortex 
  of 
  the 
  twigs. 
  A. 
  piri, 
  

   Boyer, 
  is 
  distinct 
  from 
  A. 
  piri, 
  Koch, 
  which 
  lives 
  partly 
  on 
  the 
  pear 
  

   and 
  partly 
  on 
  coltsfoot. 
  

  

  Aphis 
  grossulariae, 
  Kalt., 
  infests 
  red 
  currants 
  and 
  gooseberries. 
  

   Numerous 
  wingless 
  individuals 
  were 
  found 
  late 
  in 
  May 
  ; 
  the 
  stem- 
  

   mother 
  which 
  had 
  given 
  rise 
  to 
  these 
  was 
  apparently 
  winged, 
  but 
  this 
  

   was 
  not 
  determined 
  with 
  certainty. 
  Later, 
  winged 
  individuals 
  

   appeared 
  which 
  migrated 
  from 
  Ribes 
  ; 
  the 
  second 
  host 
  plant 
  was 
  

   not 
  found, 
  nor 
  did 
  the 
  lice 
  appear 
  on 
  Ribes 
  again 
  in 
  the 
  autumn 
  in 
  

   order 
  to 
  oviposit. 
  

  

  Macrosiphum 
  cereale, 
  Kalt., 
  the 
  corn 
  louse, 
  was 
  traced 
  to 
  the 
  black- 
  

   berry 
  ; 
  in 
  spring 
  the 
  stem-mother 
  was 
  found 
  on 
  the 
  blackberry 
  and 
  

   also 
  its 
  offspring, 
  which 
  consisted 
  of 
  winged 
  and 
  wingless 
  individuals 
  ; 
  

   the 
  winged 
  forms 
  migrated 
  to 
  various 
  grasses 
  where 
  they 
  gave 
  rise 
  

   parthenogenetically 
  to 
  winged 
  males 
  and 
  females 
  ; 
  these 
  returned 
  to 
  

   the 
  blackberry, 
  where 
  another 
  generation 
  of 
  females 
  was 
  produced 
  

   parthenogenetically, 
  these 
  being 
  the 
  true 
  females. 
  The 
  eggs 
  were 
  

   laid 
  in 
  the 
  buds 
  and 
  on 
  the 
  twigs 
  of 
  the 
  blackberry 
  The 
  author 
  

   confirms 
  Mordwilko's 
  suggestion 
  that 
  Schizoneura 
  piri 
  is 
  the 
  true 
  

   female 
  of 
  S. 
  lanuginosa. 
  Schizoneura 
  idmi 
  was 
  found 
  by 
  the 
  author 
  

   on 
  Ribes 
  rubrum, 
  nigrum, 
  grossularia, 
  alpinum, 
  and 
  aureum. 
  The 
  

   migrations 
  of 
  the 
  following 
  species 
  of 
  less 
  economic 
  importance 
  are 
  

   described 
  : 
  Aphis 
  rumicis, 
  Siphocoryne 
  saliceti, 
  Rhopalosiphum 
  

   lonicerae, 
  Hamamelistes 
  betulinus 
  and 
  Tullgrenia 
  phaseoli. 
  

  

  