﻿334 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  pendages, 
  an 
  enlarged 
  thoracic 
  region, 
  and 
  a 
  long 
  ten-jointed 
  abdomen, 
  

   slightly 
  tapering, 
  with 
  each 
  segment 
  bearing 
  bundles 
  of 
  hairs. 
  From 
  the 
  

   eighth 
  abdominal 
  segment 
  a 
  long 
  tubular 
  organ 
  is 
  given 
  out, 
  ending 
  in 
  

   a 
  star-like 
  structure 
  bearing 
  a 
  number 
  of 
  ciliae. 
  This 
  is 
  its 
  organ 
  of 
  res- 
  

   piration 
  — 
  all 
  the 
  air 
  that 
  it 
  receives 
  being 
  supplied 
  to 
  the 
  tracheal 
  vessels 
  

   only 
  through 
  this 
  opening. 
  The 
  terminal 
  joint 
  of 
  the 
  abdomen 
  bears 
  

   five 
  conical 
  plates 
  which 
  are 
  used 
  in 
  its 
  locomotion. 
  

  

  The 
  Pupal 
  Mosquito. 
  

  

  After 
  several 
  moltings, 
  while 
  they 
  rapidly 
  increase 
  in 
  size, 
  the 
  larvae 
  

   enter 
  upon 
  their 
  third 
  stage 
  of 
  existence, 
  in 
  assuming 
  the 
  pupal 
  stage. 
  

   At 
  this 
  time 
  they 
  present 
  an 
  uncouth 
  aspect. 
  Their 
  thoracic 
  region 
  has 
  

   become 
  greatly 
  enlarged, 
  and 
  in 
  front 
  of 
  it 
  are 
  grouped, 
  in 
  separate 
  cases, 
  

   the 
  legs, 
  wings, 
  mouth-parts 
  and 
  antennae. 
  They 
  still 
  continue 
  in 
  an 
  

   active 
  state, 
  unlike 
  the 
  quiescent 
  pupal 
  condition 
  of 
  many 
  insects, 
  

   and 
  even 
  many 
  other 
  Diptera 
  — 
  but 
  they 
  are 
  incapable 
  of 
  feeding. 
  A 
  

   striking 
  and 
  interesting 
  change 
  has 
  taken 
  place 
  in 
  their 
  breathing 
  

   apparatus. 
  They 
  suspend 
  themselves 
  from 
  the 
  surface 
  of 
  the 
  water, 
  as 
  

   before, 
  for 
  respiration, 
  but 
  the 
  air 
  is 
  now 
  taken 
  in 
  through 
  two 
  horn- 
  

   shaped 
  organs 
  proceeding 
  from 
  the 
  upper 
  part 
  of 
  the 
  thorax. 
  Before, 
  

   they 
  hung 
  head 
  downward; 
  now, 
  as 
  they 
  have 
  made 
  a 
  material 
  advance 
  

   in 
  development, 
  more 
  fittingly, 
  head 
  upward. 
  

  

  In 
  about 
  two 
  weeks, 
  usually, 
  from 
  the 
  deposit 
  of 
  the 
  eggs, 
  the 
  pupal 
  

   stage 
  is 
  completed, 
  and 
  the 
  insect 
  is 
  prepared 
  to 
  enter 
  upon 
  its 
  final 
  state, 
  

   a 
  perfect, 
  winged 
  insect. 
  With 
  so 
  brief 
  a 
  period 
  required 
  for 
  its 
  develop- 
  

   ment, 
  you 
  will 
  perceive 
  that 
  there 
  is 
  ample 
  time 
  for 
  several 
  generations 
  of 
  

   the 
  insect 
  during 
  the 
  spring 
  and 
  summer 
  months. 
  

  

  The 
  Final 
  Development. 
  

  

  The 
  pupa 
  having 
  fully 
  matured, 
  it 
  rises 
  to 
  the 
  surface 
  of 
  the 
  water 
  

   where 
  it 
  floats 
  with 
  its 
  thorax 
  elevated 
  above 
  the 
  surface. 
  Exposure 
  to 
  

   the 
  air 
  dries 
  the 
  exposed 
  portion, 
  and, 
  aided 
  by 
  movements 
  within, 
  it 
  

   splits 
  along 
  the 
  middle 
  line, 
  and 
  the 
  head 
  and 
  thorax 
  of 
  the 
  inclosed 
  in- 
  

   sect 
  are 
  thrust 
  out. 
  Slowly 
  the 
  wings, 
  legs, 
  other 
  organs 
  and 
  abdomen 
  

   are 
  drawn 
  forth 
  through 
  alternating 
  muscular 
  extension 
  and 
  contraction 
  — 
  

   all 
  the 
  while 
  balancing 
  itself 
  in 
  an 
  upright 
  position 
  with 
  the 
  utmost 
  care, 
  

   for 
  the 
  problem 
  of 
  how 
  to 
  maintain 
  the 
  center 
  of 
  gravity 
  when 
  elevated 
  

   so 
  high 
  above 
  its 
  frail 
  and 
  unstable 
  base 
  must 
  necessarily 
  be 
  an 
  exceed- 
  

   ingly 
  difficult 
  one 
  — 
  it 
  would 
  seem 
  to 
  be 
  an 
  impossibility. 
  The 
  slightest 
  

  

  