﻿2.^6 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  Seventeen 
  years, 
  less 
  the 
  few 
  weeks 
  spent 
  in 
  the 
  adult 
  and 
  egg 
  states 
  

   above 
  ground, 
  are 
  passed 
  by 
  this 
  insect 
  in 
  slow 
  growth 
  and 
  development 
  

   below 
  the 
  surface. 
  There 
  is 
  but 
  little 
  change, 
  except 
  increase 
  in 
  size, 
  in 
  

   the 
  appearance 
  of 
  the 
  larva 
  during 
  this 
  long 
  period, 
  but 
  toward 
  its 
  close 
  

   there 
  may 
  be 
  noticed 
  four 
  scale-like 
  appendages 
  which 
  represent 
  the 
  

   rudimentary 
  wings. 
  These 
  have 
  been 
  gradually 
  developed 
  during 
  the 
  

   later 
  stages 
  of 
  the 
  larval 
  existence. 
  The 
  emergence 
  of 
  the 
  insect 
  from 
  

   its 
  underground 
  retreat, 
  although 
  separated 
  by 
  such 
  a 
  long 
  period 
  of 
  

   years, 
  is 
  remarkably 
  punctual, 
  rarely 
  varying 
  more 
  than 
  a 
  few 
  days 
  from 
  

   the 
  usual 
  time. 
  In 
  the 
  spring 
  of 
  the 
  seventeenth 
  year 
  the 
  larva 
  makes 
  

   its 
  way, 
  sometimes 
  with 
  great 
  difficulty 
  from 
  obstacles 
  encountered, 
  to 
  

   near 
  the 
  surface 
  through 
  a 
  circuitous, 
  smooth, 
  and 
  firmly 
  compacted 
  gal- 
  

   lery, 
  of 
  a 
  diameter 
  barely 
  sufficient 
  to 
  permit 
  its 
  passage. 
  In 
  its 
  upper 
  

   portion, 
  at 
  the 
  proper 
  time, 
  it 
  transforms 
  to 
  the 
  pupa, 
  which 
  in 
  turn 
  forsakes 
  

   the 
  gallery 
  just 
  before 
  it 
  is 
  ready 
  to 
  assume 
  the 
  perfect 
  form 
  and 
  climbs 
  the 
  

   nearest 
  tree 
  or 
  other 
  support.* 
  Here 
  the 
  pupa 
  fixes 
  itself 
  firmly 
  and 
  awaits 
  

   the 
  time 
  for 
  the 
  final 
  change. 
  The 
  pupal 
  shell 
  (PI. 
  IX, 
  fig. 
  2) 
  soon 
  

   splits 
  along 
  the 
  back 
  and 
  the 
  creamy-white 
  adult 
  with 
  its 
  red 
  eyes 
  and 
  

   the 
  black 
  spots 
  on 
  the 
  thorax 
  works 
  itself 
  slowly 
  out 
  of 
  the 
  old 
  case. 
  It 
  

   is 
  soft 
  just 
  after 
  emerging, 
  and 
  as 
  it 
  dries, 
  the 
  parts 
  begin 
  to 
  harden 
  and 
  

   slowly 
  to 
  assume 
  the 
  colors 
  natural 
  to 
  the 
  perfect 
  insect. 
  

  

  The 
  cold 
  weather 
  that 
  prevailed 
  for 
  the 
  first 
  week 
  or 
  two 
  of 
  their 
  

   appearance, 
  in 
  1894, 
  resulted 
  fatally 
  to 
  many, 
  and 
  large 
  numbers 
  of 
  the 
  

   dead 
  might 
  be 
  seen 
  lying 
  upon 
  the 
  ground 
  or 
  clinging 
  to 
  the 
  trees, 
  — 
  in 
  the 
  

   latter 
  case 
  often 
  half-way 
  out 
  of 
  the 
  pupal 
  shell. 
  The 
  adults 
  live 
  several 
  

   weeks, 
  feeding 
  at 
  will 
  by 
  means 
  of 
  their 
  beak 
  on 
  the 
  sap 
  of 
  trees. 
  After 
  

   pairing, 
  oviposition 
  occurs, 
  and 
  the 
  long 
  life-cycle 
  of 
  another 
  brood 
  is 
  

   commenced. 
  

  

  A 
  Thirteen-Year 
  Brood. 
  

  

  In 
  the 
  Northern 
  States 
  of 
  the 
  Union 
  this 
  insect 
  occupies 
  seventeen 
  

   years 
  in 
  completing 
  its 
  round 
  of 
  hfe 
  as 
  stated 
  above, 
  but 
  in 
  the 
  Southern 
  

   States, 
  ranging 
  as 
  far 
  north 
  as 
  southern 
  Illinois, 
  there 
  is 
  a 
  form 
  which 
  re- 
  

   quires 
  but 
  thirteen 
  years 
  for 
  its 
  transformations. 
  It 
  is 
  to 
  all 
  appearances 
  

   identical 
  with 
  the 
  one 
  occurring 
  m 
  the 
  Northern 
  States, 
  except 
  in 
  a 
  few 
  

   minor 
  detai's. 
  The 
  greater 
  length 
  of 
  the 
  growing 
  season 
  in 
  the 
  south 
  

   may 
  perhaps 
  account 
  for 
  the 
  quicker 
  development 
  of 
  the 
  larva. 
  Dr. 
  

   Riley 
  was 
  of 
  the 
  opinion 
  that 
  the 
  tliirteen-year 
  for 
  n 
  was 
  but 
  a 
  race 
  of 
  

   C. 
  sfptejideciin, 
  and 
  nOt 
  a 
  distinct 
  species. 
  

  

  * 
  Under 
  certain 
  conditions 
  tlie 
  hirva 
  extends 
  the 
  g^allery 
  into 
  an 
  above-ground 
  earthcrn 
  chamber, 
  

   ■which 
  will 
  be 
  noticed 
  hereafter. 
  

  

  