﻿36 
  THE 
  BEAN 
  THKIPS. 
  

  

  TOTAL 
  LIFE 
  CYCLE. 
  

  

  For 
  localities 
  with 
  climatic 
  conditions 
  similar 
  to 
  those 
  of 
  Compton, 
  

   the 
  life 
  cycle 
  of 
  this 
  thrips 
  will 
  occupy 
  during 
  the 
  early 
  spring 
  about 
  

   51 
  to 
  56 
  days, 
  taking 
  20 
  days 
  for 
  the 
  egg 
  incubation, 
  17 
  to 
  19 
  days 
  

   for 
  the 
  larval 
  development, 
  and 
  14 
  to 
  17 
  days 
  for 
  the 
  prepupal 
  and 
  

   pupal 
  stages. 
  

  

  During 
  the 
  months 
  of 
  June 
  to 
  October 
  the 
  life 
  cycle 
  of 
  this 
  thrips 
  

   will 
  occupy 
  from 
  28 
  to 
  43 
  days, 
  taking 
  13 
  to 
  18 
  days 
  for 
  the 
  egg 
  

   stage, 
  10 
  to 
  14 
  days 
  for 
  the 
  larval 
  stage, 
  and 
  5 
  to 
  11 
  days 
  for 
  the 
  

   prepupal 
  and 
  pupal 
  stages. 
  

  

  During 
  the 
  rest 
  of 
  the 
  breeding 
  activity 
  the 
  life 
  cycle 
  must 
  be 
  even 
  

   longer 
  than 
  in 
  the 
  spring, 
  as 
  in 
  November, 
  1910, 
  the 
  prepupal 
  and 
  

   pupal 
  stages 
  alone 
  occupied 
  from 
  28 
  to 
  33 
  days, 
  so 
  that 
  for 
  the 
  de- 
  

   velopment 
  of 
  this 
  insect 
  during 
  October, 
  November, 
  and 
  the 
  first 
  of 
  

   December 
  at 
  least 
  68 
  to 
  73 
  days 
  must 
  be 
  required. 
  

  

  EMERGENCE 
  FROM 
  HIBERNATION. 
  

  

  In 
  1912 
  the 
  adults 
  began 
  to 
  emerge 
  from 
  hibernation 
  at 
  Holly- 
  

   wood, 
  Cal., 
  in 
  January, 
  and 
  began 
  oviposition 
  at 
  once. 
  When 
  this 
  

   locality 
  was 
  visited 
  on 
  February 
  7, 
  the 
  adults 
  were 
  found 
  to 
  be 
  feed- 
  

   ing 
  on 
  the 
  foliage 
  of 
  peas 
  and 
  beans 
  in 
  some 
  numbers. 
  They 
  were 
  

   also 
  seen 
  in 
  copulation 
  in 
  many 
  cases. 
  A 
  careful 
  examination 
  dis- 
  

   closed 
  4 
  young 
  larvae 
  feeding 
  on 
  bean 
  foliage, 
  so 
  that 
  the 
  adult 
  must 
  

   have 
  laid 
  the 
  eggs 
  at 
  least 
  by 
  January 
  10. 
  This 
  field 
  was 
  situated 
  

   on 
  the 
  foothills 
  of 
  what 
  is 
  termed 
  a 
  frostless 
  belt, 
  and 
  it 
  may 
  be 
  that 
  

   tliis 
  insect 
  in 
  mild 
  winters 
  might 
  breed 
  there 
  during 
  the 
  entire 
  

   period. 
  

  

  On 
  February 
  17 
  adults 
  were 
  found 
  feeding 
  on 
  pea 
  foliage 
  in 
  Mis- 
  

   sion 
  Valley, 
  San 
  Diego 
  County, 
  but 
  no 
  young 
  were 
  seen. 
  February 
  

   23 
  the 
  species 
  was 
  found 
  as 
  an 
  adult 
  feeding 
  on 
  pea 
  vines 
  in 
  the 
  truck 
  

   farms 
  around 
  Los 
  Angeles, 
  and 
  on 
  March 
  13 
  adults 
  were 
  found 
  feed- 
  

   ing 
  in 
  small 
  numbers 
  at 
  Compton, 
  Cal. 
  From 
  then 
  on 
  the 
  adults 
  were 
  

   common 
  feeding 
  on 
  different 
  plants, 
  but 
  not 
  until 
  April 
  17 
  were 
  the 
  

   larvse 
  found 
  feeding 
  in 
  the 
  open 
  at 
  Compton, 
  although 
  they 
  were 
  

   being 
  reared 
  in 
  the 
  open 
  insectary 
  at 
  that 
  place 
  from 
  material 
  col- 
  

   lected 
  at 
  Hollywood. 
  

  

  It 
  would 
  probably 
  be 
  better 
  to 
  say 
  that 
  this 
  insect 
  begins 
  active 
  

   reproduction 
  at 
  a 
  varying 
  time, 
  those 
  in 
  the 
  most 
  protected 
  places 
  

   starting 
  as 
  early 
  as 
  January 
  10, 
  and 
  the 
  others 
  over 
  the 
  next 
  60 
  day 
  s. 
  

   However, 
  during 
  the 
  early 
  spring 
  the 
  multiplication 
  and 
  spread 
  

   seem 
  to 
  be 
  very 
  slow. 
  

  

  ENTRANCE 
  INTO 
  HIBERNATION. 
  

  

  As 
  the 
  month 
  of 
  October 
  appears, 
  the 
  adults 
  become 
  sluggish, 
  do 
  

   less 
  feeding 
  and 
  lay 
  fewer 
  eggs, 
  and 
  apparently 
  many 
  enter 
  hiberna- 
  

  

  