﻿18 
  

  

  the 
  mother; 
  tlio 
  fixed 
  and 
  motionless 
  scale 
  insect, 
  male 
  or 
  female 
  — 
  

   the 
  form 
  commonly 
  seen 
  upon 
  the 
  tree, 
  and 
  the 
  active 
  two-winged 
  

   male, 
  which 
  emerges 
  from 
  the 
  so-called 
  male 
  scale 
  after 
  a 
  period 
  of 
  

   development 
  to 
  which 
  nothing 
  in 
  the 
  life 
  history 
  of 
  the 
  other 
  sex 
  

   corresponds. 
  As 
  seen 
  during 
  the 
  winter 
  months, 
  the 
  male 
  and 
  female 
  

   scales 
  of 
  various 
  ages 
  -most 
  of 
  them, 
  however, 
  nearly 
  or 
  quite 
  full- 
  

   grown 
  — 
  are 
  mingled 
  in 
  the 
  same 
  incrusting 
  group 
  or 
  colony. 
  

  

  The 
  male 
  scales 
  give 
  origin 
  early 
  in 
  spring 
  to 
  the 
  winged 
  male, 
  

   which, 
  flying 
  about, 
  fertilizes 
  the 
  female 
  sheltered 
  beneath 
  their 
  sep- 
  

   arate 
  scales, 
  and 
  from 
  these, 
  living 
  young 
  are 
  born 
  — 
  from 
  the 
  first 
  of 
  

   May 
  to 
  early 
  in 
  June 
  in 
  Illinois 
  according 
  to 
  the 
  part 
  of 
  the 
  State 
  and 
  

   the 
  weather 
  of 
  the 
  season. 
  The 
  active 
  young 
  scale 
  retains 
  its 
  power 
  

   of 
  locomotion, 
  at 
  least 
  under 
  ordinary 
  conditions, 
  only 
  a 
  few 
  hours, 
  

   when 
  it 
  slowly 
  pushes 
  its 
  long 
  and 
  very 
  slender 
  beak 
  through 
  the 
  

   bark 
  into 
  the 
  living 
  tissue 
  of 
  the 
  tree, 
  contracts 
  into 
  a 
  nearly 
  circu- 
  

   lar 
  form, 
  and 
  emits 
  delicate 
  waxy 
  filaments 
  from 
  special 
  glands, 
  

   which 
  form 
  first 
  a 
  matt.ed 
  covering 
  and 
  then, 
  by 
  fusion 
  of 
  the 
  fila- 
  

   ments, 
  a 
  smooth 
  waxy 
  scale. 
  Under 
  this 
  scale 
  the 
  insect 
  lives 
  and 
  

   grows, 
  and 
  presently 
  sheds 
  its 
  crust 
  or 
  skin, 
  without 
  escaping, 
  how- 
  

   ever, 
  from 
  its 
  protective 
  covering. 
  With 
  successive 
  molts 
  the 
  males 
  

   go 
  through 
  their 
  special 
  metamorphoses, 
  forming 
  wing-pads 
  within 
  

   which 
  the 
  wings 
  develop, 
  while 
  the 
  female 
  simply 
  grows 
  and 
  becomes 
  

   sexually 
  mature. 
  Four 
  successive 
  generations 
  were 
  observed 
  at 
  

   Washington 
  in 
  a 
  single 
  season, 
  with 
  some 
  indications 
  of 
  a 
  fifth. 
  The 
  

   period 
  from 
  birth 
  to 
  maturity 
  was 
  from 
  thirty-three 
  to 
  forty 
  days. 
  

  

  The 
  number 
  of 
  young 
  produced 
  by 
  a 
  single 
  female 
  under 
  observa- 
  

   tion 
  has 
  risen 
  as 
  high 
  as 
  five 
  hundred 
  and 
  eighty-six, 
  four 
  hundred 
  

   and 
  sixty-four 
  of 
  which 
  were 
  females. 
  Howard 
  estimates 
  two 
  hun- 
  

   dred 
  females 
  as 
  a 
  general 
  average 
  of 
  the 
  different 
  generations 
  of 
  the 
  

   year, 
  according 
  to 
  which 
  the 
  product 
  of 
  a 
  single 
  individual 
  from 
  

   spring 
  to 
  fall 
  might 
  conceivably 
  amount 
  to 
  a 
  billion 
  and 
  a 
  half 
  of 
  

   female 
  scales, 
  or 
  to 
  three 
  and 
  a 
  quarter 
  billions 
  of 
  both 
  sexes. 
  "It 
  

   is 
  not 
  to 
  be 
  expected, 
  of 
  course," 
  says 
  Mr. 
  Howard, 
  ''that 
  all 
  the 
  in- 
  

   dividuals 
  from 
  a 
  scale 
  survive 
  and 
  perform 
  their 
  function 
  in 
  life, 
  but 
  

   under 
  favorable 
  conditions, 
  or 
  in 
  the 
  case 
  of 
  a 
  tree 
  newly 
  infested 
  or 
  

   not 
  heavily 
  incrusted, 
  the 
  vast 
  majority 
  undoubtedly 
  go 
  through 
  

   their 
  existence 
  without 
  accident. 
  Neither 
  the 
  rapidity 
  with 
  which 
  

   trees 
  become 
  infested 
  nor 
  the 
  fatal 
  effect 
  which 
  so 
  early 
  follows 
  the 
  

   appearance 
  of 
  this 
  scale 
  insect 
  is 
  therefore 
  to 
  be 
  wondered 
  at." 
  

  

  N.A.TIK.AL 
  CHECKS 
  ON 
  MULTIPLIC.\TION. 
  

  

  The 
  economic 
  history 
  of 
  the 
  San 
  Jose 
  scale 
  in 
  California, 
  where 
  it 
  

   has 
  l)een 
  longest 
  known 
  (for 
  twenty-five 
  years) 
  , 
  is 
  involved 
  in 
  great 
  

   confusion, 
  contradiction, 
  and 
  uncertainty, 
  owing 
  primarily 
  to 
  the 
  fact 
  

   that 
  it 
  has 
  not 
  been 
  continuously 
  followed 
  for 
  any 
  considerable 
  time 
  

   at 
  any 
  one 
  point 
  by 
  even 
  one 
  expert 
  investigator. 
  A 
  great 
  quantity 
  

   of 
  evidence 
  concerning 
  it 
  collected 
  there 
  from 
  local 
  sources 
  in 
  18% 
  

   l)y 
  Professor 
  John 
  11 
  Smith, 
  of 
  New 
  Jersey, 
  is 
  very 
  largely 
  a 
  mass 
  

   of 
  conflicting 
  views 
  and 
  mutually 
  destructive 
  interpretations 
  of 
  facts 
  

  

  