﻿LIFE 
  HISTORY. 
  

  

  11 
  

  

  THE 
  LARVA 
  AND 
  NYMPH. 
  

  

  Descriptive. 
  — 
  The 
  larva 
  (fig. 
  2) 
  is 
  a 
  minute, 
  almost 
  globular 
  object, 
  

   and 
  differs 
  from 
  the 
  adult 
  in 
  the 
  possession 
  of 
  only 
  three 
  pairs 
  of 
  legs. 
  

   This 
  six-legged 
  condition 
  lasts 
  only 
  during 
  the 
  first 
  stage, 
  i. 
  e., 
  until 
  

   the 
  first 
  molt, 
  from 
  which 
  the 
  mites 
  emerge 
  as 
  nymphs, 
  with 
  four 
  

   pairs 
  of 
  legs, 
  and, 
  except 
  for 
  size 
  and 
  the 
  maturity 
  of 
  the 
  sexual 
  

   organs, 
  similar 
  to 
  the 
  adults. 
  According 
  to 
  C. 
  H. 
  Perkins, 
  1 
  the 
  sex- 
  

   ual 
  organs 
  appear 
  with 
  the 
  second 
  molt, 
  but 
  copulation 
  does 
  not 
  take 
  

   place 
  until 
  after 
  the 
  third. 
  

  

  Length 
  of 
  stages. 
  — 
  The 
  length 
  of 
  the 
  larval 
  

   and 
  nymphal 
  periods 
  varies, 
  being 
  from 
  8 
  to 
  16 
  

   days, 
  according 
  to 
  the 
  prevailing 
  temperature. 
  

   As 
  shown 
  in 
  Table 
  I, 
  this 
  period 
  under 
  the 
  

   temperature 
  conditions 
  given 
  in 
  the 
  plat 
  was 
  

   15 
  to 
  16 
  days. 
  During 
  May, 
  however, 
  this 
  

   period 
  was 
  found 
  to 
  be 
  11 
  to 
  12 
  days 
  and 
  in 
  

   July, 
  1911, 
  which 
  was 
  an 
  exceptionally 
  warm 
  

   month, 
  two 
  mites 
  were 
  observed 
  to 
  be 
  mature 
  

   8 
  days 
  after 
  emerging 
  from 
  the 
  egg. 
  

  

  Under 
  field 
  conditions 
  in 
  1911 
  it 
  was 
  impos- 
  

   sible 
  to 
  carry 
  out 
  any 
  very 
  extensive 
  life-history 
  experiments. 
  During 
  

   the 
  winter, 
  however, 
  a 
  series 
  was 
  carried 
  out 
  in 
  the 
  insectary 
  of 
  the 
  

   University 
  of 
  California, 
  at 
  Berkeley, 
  Cal. 
  

  

  This 
  series 
  is 
  recorded 
  in 
  Table 
  I. 
  

  

  Fig. 
  2.— 
  Larva 
  of 
  the 
  red 
  spi- 
  

   der. 
  The 
  legs 
  in 
  this 
  sta.^e 
  

   are 
  transparent. 
  Greatly 
  en- 
  

   larged. 
  (Original.) 
  

  

  Table 
  I. 
  — 
  Transformations 
  and 
  length 
  of 
  stages 
  of 
  the 
  red 
  spider 
  in 
  California, 
  1912. 
  

  

  No. 
  

  

  Eggs 
  laid. 
  

  

  Hatched. 
  

  

  Length 
  

   of 
  stage. 
  

  

  First 
  molt. 
  

  

  Length 
  

  

  Date. 
  

  

  Time. 
  

  

  Date. 
  

  

  Time. 
  

  

  Date. 
  

  

  Time. 
  

  

  of 
  stage. 
  

  

  

  Feb. 
  6 
  

   6 
  

  

  ii 
  

   6 
  

  

  s 
  

  

  9 
  a. 
  m 
  

  

  9 
  a. 
  m 
  

  

  1 
  p. 
  m 
  

  

  3.30 
  p. 
  m.. 
  

  

  8 
  a. 
  m 
  

  

  3 
  p. 
  m 
  

  

  9 
  a. 
  m 
  

  

  Feb. 
  16 
  

   15 
  

   16 
  

   16 
  

   16 
  

   16 
  

   16 
  

  

  8 
  a. 
  m 
  

  

  12m 
  

  

  3 
  p. 
  m 
  

  

  11 
  a. 
  m 
  

  

  3 
  p. 
  m 
  

  

  3 
  p. 
  m 
  

  

  3 
  p. 
  m 
  

  

  Days. 
  

   10 
  

   9 
  

   10 
  

   10 
  

   9 
  

   8 
  

   9 
  

  

  Feb. 
  20 
  

   20 
  

   20 
  

   20 
  

   20 
  

   20 
  

   21 
  

  

  5 
  p. 
  m. 
  . 
  

   9 
  a. 
  m... 
  

   4 
  }>. 
  m. 
  . 
  

   4p. 
  m... 
  

   9 
  a. 
  m. 
  . 
  . 
  

   9 
  a. 
  m. 
  .. 
  

   4 
  p. 
  m... 
  

  

  Days. 
  

  

  5 
  

   4 
  

  

  2 
  

  

  3 
  

  

  4 
  

  

  4, 
  

   3| 
  

  

  5 
  

  

  6 
  

  

  L3j 
  

  

  7. 
  

  

  

  

  

  No. 
  

  

  Second 
  molt. 
  

  

  Length 
  

   of 
  stage. 
  

  

  Third 
  molt. 
  

  

  Length 
  

   of 
  stage. 
  

  

  First 
  egg 
  laid. 
  

  

  Total 
  

   time, 
  egg 
  

   to 
  adult 
  

  

  Date. 
  

  

  Time. 
  

  

  Date. 
  

  

  Time. 
  

  

  Date. 
  

  

  Time. 
  

  

  1 
  

  

  2 
  

  

  3 
  

  

  Fel). 
  25 
  

   25 
  

   25 
  

   25 
  

   25 
  

   25 
  

   25 
  

  

  4 
  p. 
  m... 
  

   4 
  p. 
  m... 
  

   4 
  \>. 
  m... 
  

   4 
  p. 
  m... 
  

   4 
  p. 
  m... 
  

   ( 
  .i 
  a. 
  in. 
  . 
  . 
  

   1 
  p. 
  in... 
  

  

  Days. 
  

   5 
  

  

  5 
  

  

  5J 
  

  

  5 
  

  

  4 
  

  

  Feb. 
  29 
  

   29 
  

   29 
  

   29 
  

  

  9 
  a. 
  m 
  

  

  9 
  a. 
  m 
  

  

  9 
  a. 
  m 
  

  

  '.I 
  a. 
  m 
  

  

  Days. 
  

   31 
  

  

  Mar. 
  2 
  

   2 
  

  

  11 
  a. 
  in.. 
  

   11 
  a. 
  m.. 
  

  

  Days. 
  

  

  25 
  

  

  25 
  

  

  4 
  

  

  5 
  

  

  2 
  

   2 
  

   2 
  

   3 
  

  

  1 
  1 
  a. 
  in 
  . 
  

   11 
  a. 
  in.. 
  

   1 
  1 
  a. 
  in. 
  . 
  

   1 
  1 
  a. 
  in. 
  . 
  

  

  25 
  

  

  21 
  

  

  6 
  

  

  7 
  

  

  29 
  

  

  Mar. 
  1 
  

  

  '» 
  a. 
  in 
  

  

  11 
  a. 
  m 
  

  

  4 
  

  

  23 
  

  

  25 
  

  

  Report 
  of 
  tin) 
  Vermont 
  Agricultural 
  Experiment 
  Station, 
  1896 
  '.'7. 
  

  

  