﻿667 
  

  

  is 
  advised. 
  Tobacco 
  dust 
  had 
  no 
  effect 
  upon 
  the 
  larvae. 
  Lead 
  

   arsenate, 
  1 
  per 
  cent, 
  solution 
  combined 
  with 
  Bordeaux 
  mixture, 
  gave 
  

   good 
  results, 
  either 
  as 
  a 
  spray 
  or 
  when 
  used 
  for 
  dipping 
  the 
  young 
  

   bunches. 
  Lead 
  arsenate 
  against 
  the 
  first 
  generation 
  of 
  larvae 
  is 
  hkely 
  

   to 
  give 
  the 
  best 
  results 
  until 
  a 
  reliable 
  standard 
  of 
  nicotin 
  extract 
  

   can 
  be 
  obtained. 
  During 
  July 
  and 
  August 
  it 
  is 
  better 
  to 
  use 
  tobacco 
  

   extract, 
  2 
  to 
  2*5 
  per 
  cent., 
  as 
  it 
  acts 
  as 
  an 
  insectifuge 
  and 
  avoids 
  the 
  

   difficulties 
  of 
  arsenate. 
  The 
  treatment 
  should 
  not 
  continue 
  later 
  

   than 
  the 
  first 
  few 
  days 
  of 
  August, 
  owing 
  to 
  the 
  danger 
  of 
  affecting 
  

   the 
  flavour 
  of 
  the 
  ^dne. 
  The 
  spray 
  should 
  be 
  made 
  to 
  cover 
  neighbour- 
  

   ing 
  shoots, 
  as 
  the 
  moths 
  driven 
  from 
  the 
  bunches 
  of 
  grapes 
  would 
  

   deposit 
  their 
  eggs 
  on 
  the 
  leaves, 
  and 
  the 
  larvae 
  might 
  reach 
  the 
  fruit. 
  

   All 
  possible 
  hibernating 
  places 
  must 
  be 
  removed, 
  the 
  vine-stocks 
  

   cleaned, 
  and 
  in 
  small 
  vineyards 
  handpicking 
  in 
  addition 
  to 
  the 
  use 
  

   of 
  insecticides 
  should 
  be 
  resorted 
  to. 
  Many 
  pupae 
  may 
  be 
  trapped 
  

   by 
  placing 
  dark 
  muslin 
  or 
  bunches 
  of 
  straw 
  among 
  the 
  old 
  wood 
  of 
  

   the 
  vines. 
  Badly 
  attacked 
  grapes 
  should 
  be 
  placed 
  in 
  tubs 
  covered 
  

   with 
  fine 
  netting 
  and 
  exposed, 
  so 
  that 
  parasites 
  may 
  escape. 
  

  

  HoLLRUNG 
  (M.). 
  Beitrage 
  zur 
  Kenntnis 
  der 
  Eichen-Phylloxera. 
  L 
  Die 
  

   Entwicklungsgeschichte 
  der 
  Laus. 
  [Contributions 
  to 
  the 
  knowledge 
  

   of 
  Oak 
  Phylloxera. 
  I. 
  The 
  life-history 
  of 
  the 
  louse.] 
  — 
  Kuhn- 
  

   Archiv, 
  Berlin, 
  v, 
  1914, 
  pp. 
  347-382, 
  5 
  figs. 
  

  

  In 
  view 
  of 
  the 
  uncertainty 
  regarding 
  the 
  identity 
  of 
  the 
  several 
  

   species 
  of 
  Phylloxera 
  found 
  on 
  the 
  oak, 
  the 
  various 
  communications 
  

   on 
  the 
  subject, 
  from 
  the 
  discovery 
  of 
  the 
  genus 
  down 
  to 
  1909, 
  are 
  

   recorded. 
  The 
  species 
  on 
  which 
  the 
  present 
  observations 
  are 
  based 
  

   is 
  thought 
  to 
  be 
  Phylloxera 
  quercus, 
  Boyer 
  de 
  Fonscolombe, 
  though 
  

   according 
  to 
  Borner 
  it 
  is 
  P. 
  coccinea. 
  The 
  oak 
  phylloxera 
  hibernates 
  

   in 
  the 
  form 
  of 
  a 
  winter-egg 
  in 
  cracks 
  of 
  the 
  bark 
  or 
  of 
  dried 
  leaf-buds. 
  

   The 
  insect 
  itself 
  does 
  not 
  hibernate 
  above 
  ground, 
  though 
  whether 
  

   it 
  does 
  so 
  below 
  ground 
  is 
  uncertain. 
  After 
  hatching, 
  the 
  young 
  

   fundatrix 
  moves 
  actively 
  about 
  on 
  the 
  young 
  oak 
  leaves 
  for 
  a 
  short 
  

   time 
  until 
  the 
  first 
  moult, 
  when 
  it 
  fixes 
  itself 
  on 
  the 
  underside 
  of 
  a 
  

   leaf 
  close 
  to 
  a 
  vein. 
  In 
  two 
  or 
  three 
  days 
  the 
  edge 
  of 
  the 
  leaf 
  folds 
  

   downwards 
  and 
  backwards 
  until 
  it 
  lies 
  flat 
  against 
  the 
  underside. 
  

   Only 
  one 
  fundatrix 
  is 
  found 
  in 
  a 
  fold, 
  except 
  in 
  cases 
  of 
  severe 
  

   infestation. 
  In 
  1911, 
  the 
  first 
  generation 
  was 
  completed 
  by 
  the 
  end 
  

   of 
  May 
  and 
  the 
  young 
  of 
  the 
  second 
  were 
  already 
  noticeable 
  on 
  the 
  

   15th 
  May, 
  becoming 
  abundant 
  at 
  the 
  end 
  of 
  that 
  month. 
  On 
  the 
  

   6th 
  June, 
  the 
  first 
  eggs 
  laid 
  by 
  the 
  mothers 
  from 
  the 
  second 
  

   generation 
  were 
  noticed. 
  Feeding 
  conditions, 
  which 
  are 
  dependent 
  

   on 
  weather 
  conditions, 
  are 
  the 
  factors 
  governing 
  the 
  appearance 
  of 
  

   winged 
  forms. 
  Dry 
  weather 
  cuts 
  short 
  the 
  supply 
  of 
  moisture 
  in 
  

   the 
  leaf 
  and 
  the 
  insects 
  assume 
  the 
  winged 
  form 
  and 
  migrate, 
  those 
  

   individuals 
  which 
  are 
  favourably 
  placed 
  for 
  obtaining 
  moisture 
  

   remaining 
  untransformed. 
  In 
  Italy, 
  the 
  first 
  generation 
  usually 
  

   transforms 
  in 
  spring, 
  but 
  on 
  the 
  Igelsberg 
  (between 
  Naumburg 
  and 
  

   Weissenfels 
  on 
  the 
  Saale) 
  the 
  transformation 
  of 
  second 
  generation 
  

   individuals 
  in 
  the 
  dry 
  year 
  of 
  1911 
  only 
  occurred 
  on 
  heavily 
  

   infested 
  leaves. 
  In 
  1910, 
  the 
  leaves 
  were 
  full 
  of 
  sap 
  and 
  no 
  nymphs 
  

   of 
  the 
  second 
  generation 
  were 
  observed. 
  The 
  nymphs 
  of 
  the 
  third 
  

  

  