﻿22 
  

  

  THE 
  BEAN 
  THKIPS. 
  

  

  LEAPING. 
  

  

  This 
  species 
  possesses 
  the 
  power 
  to 
  leap 
  actively 
  and, 
  considering 
  

   its 
  size, 
  to 
  a 
  considerable 
  distance. 
  It 
  is 
  no 
  uncommon 
  occurrence 
  for 
  

   the 
  specimens 
  which 
  are 
  being 
  examined 
  upon 
  a 
  plant 
  to 
  leap 
  off 
  and 
  

   be 
  lost. 
  Like 
  the 
  greenhouse 
  thrips, 
  it 
  will 
  crawl 
  over 
  the 
  leaves 
  

   rapidly 
  when 
  disturbed. 
  At 
  other 
  times 
  it 
  will 
  remain 
  motionless 
  

   for 
  a 
  considerable 
  period, 
  lying 
  closely 
  to 
  the 
  surface 
  of 
  the 
  leaf 
  along 
  

   one 
  of 
  the 
  veins. 
  

  

  NORMAL 
  LENGTH 
  OF 
  LIFE. 
  

  

  The 
  length 
  of 
  life 
  of 
  this 
  insect 
  as 
  an 
  adult 
  has 
  been 
  determined 
  

   under 
  the 
  artificial 
  conditions 
  of 
  confinement 
  in 
  vials 
  containing 
  

   fresh 
  leaves 
  of 
  the 
  food 
  plant. 
  As 
  often 
  as 
  these 
  lost 
  their 
  freshness 
  

   other 
  leaves 
  were 
  put 
  in 
  and 
  the 
  adults 
  were 
  changed 
  with 
  a 
  camel 
  's- 
  

   hair 
  brush. 
  

  

  Even 
  under 
  these 
  conditions 
  the 
  length 
  of 
  life 
  observed 
  for 
  some 
  

   individuals 
  was 
  surprisingly 
  long, 
  when 
  we 
  consider 
  the 
  minute 
  size 
  

   of 
  the 
  insect. 
  During 
  these 
  experiments 
  it 
  was 
  observed 
  that 
  these 
  

   insects 
  were 
  very 
  sensitive 
  to 
  humidity 
  or 
  a 
  lack 
  of 
  it 
  and 
  all 
  were 
  

   soon 
  killed 
  whenever 
  the 
  vials 
  used 
  in 
  confining 
  them 
  became 
  too 
  dry. 
  

   Table 
  II 
  shows 
  the 
  results 
  of 
  these 
  experiments 
  in 
  which 
  some 
  thrips 
  

   lived 
  for 
  84 
  days. 
  

  

  Table 
  II. 
  — 
  Length 
  of 
  life 
  of 
  adult 
  bean 
  thrips 
  wt 
  Compton, 
  Cal~ 
  1911. 
  

  

  Date 
  adults 
  emerged 
  from 
  pupa. 
  

  

  Number 
  

   emerged. 
  

  

  Specimens 
  died. 
  

  

  Last 
  

   adult 
  

   died. 
  

  

  

  

  

  Date. 
  

  

  Number. 
  

  

  3 
  

  

  /May 
  8 
  

   \May 
  11 
  

  

  1 
  

   1 
  

  

  JMay 
  22 
  

  

  

  |May 
  8 
  

  

  f 
  i2 
  

  

  ; 
  

  

  11 
  

  

  I 
  May 
  18 
  

  

  1 
  

  

  ijulv 
  14 
  3 
  

  

  

  May 
  26 
  

  

  1 
  

  

  

  

  (June 
  5 
  

  

  1 
  

  

  

  9 
  

  

  /June 
  17 
  

   \June 
  21 
  

  

  5 
  

  

  3 
  

  

  }Aug. 
  14 
  

  

  

  July 
  22 
  

  

  2 
  

  

  ] 
  

  

  

  July 
  25 
  

  

  2 
  

  

  

  14 
  

  

  July 
  26 
  

   Aug. 
  8 
  

  

  2 
  

   2 
  

  

  [Aug. 
  21 
  

  

  

  Aug. 
  12 
  

  

  2 
  

  

  

  

  .Aug. 
  17 
  

  

  1 
  

  

  J 
  

  

  Maximum 
  

  

  length 
  of 
  

  

  life. 
  

  

  Days. 
  

  

  April 
  16 
  

   April 
  23 
  

   June 
  5.. 
  

  

  July 
  19. 
  

  

  37 
  

  

  84 
  

  

  71 
  

  

  34 
  

  

  i 
  Dead. 
  

  

  2 
  Lost. 
  

  

  3 
  Male 
  and 
  female. 
  

  

  LENGTH 
  OF 
  LIFE 
  IN 
  WINTER. 
  

  

  A 
  number 
  of 
  adults 
  were 
  collected 
  from 
  host 
  plants 
  on 
  November 
  

   18, 
  1910, 
  and 
  were 
  placed 
  in 
  vials 
  and 
  furnished 
  with 
  fresh 
  leaves 
  at 
  

   intervals, 
  and 
  some 
  lived 
  in 
  confinement 
  in 
  this 
  manner 
  until 
  Febru- 
  

   ary 
  1, 
  1911, 
  by 
  which 
  time 
  all 
  had 
  died. 
  On 
  January 
  16, 
  1911, 
  a 
  num- 
  

  

  