﻿AQUATIC 
  INSECTS 
  IN 
  THE 
  ADIRONDACKS 
  4I3 
  

  

  The 
  nymphs 
  of 
  stone 
  flies 
  require 
  well 
  aerated 
  water. 
  They 
  can 
  not 
  

   live 
  in 
  a 
  stagnant 
  pooH, 
  or 
  in 
  a 
  foul 
  stream. 
  A 
  large 
  number 
  of 
  the 
  

   smaller 
  species, 
  including 
  the 
  two 
  described 
  below, 
  are 
  entirely 
  destitute 
  

   of 
  gills. 
  With 
  these 
  the 
  air 
  supply 
  is 
  absorbed 
  directly 
  through 
  the 
  thin 
  

   skin 
  of 
  the 
  ventral 
  surface. 
  At 
  the 
  ventral 
  sutures 
  one 
  can 
  readily 
  see 
  

   that 
  the 
  skin 
  is 
  fully 
  permeated 
  by 
  fine 
  tracheal 
  branches. 
  Stone 
  fly 
  gills 
  

   at 
  their 
  best 
  development 
  are 
  but 
  small 
  tufts 
  of 
  delicate 
  respiratory 
  fila- 
  

   ments 
  attached 
  to 
  the 
  ventral 
  surface 
  of 
  the 
  body, 
  oftenest 
  about 
  the 
  

   bases 
  of 
  the 
  legs, 
  swished 
  about 
  by 
  the 
  motion 
  of 
  other 
  parts, 
  or 
  depend- 
  

   ent 
  on 
  the 
  motion 
  of 
  the 
  water 
  for 
  the 
  renewal 
  of 
  the 
  oxygen 
  supply. 
  

   Nymphs 
  brought 
  in 
  from 
  the 
  brook 
  and 
  placed 
  in 
  a 
  vessel 
  of 
  still 
  water 
  

   will 
  soon 
  be 
  seen 
  with 
  claws 
  affixed 
  vigorously 
  swinging 
  the 
  body 
  up 
  and 
  

   down, 
  trying 
  to 
  get 
  a 
  breath 
  under 
  the 
  difficult 
  conditions 
  into 
  which 
  tney 
  

   have 
  been 
  brought. 
  

  

  In 
  two 
  important 
  respects 
  the 
  nymphs 
  of 
  May 
  flies 
  and 
  dragon 
  flies 
  

   have 
  surpassed 
  those 
  of 
  stone 
  flies 
  in 
  the 
  development 
  of 
  aquatic 
  respira- 
  

   tory 
  apparatus 
  : 
  

  

  1 
  In 
  developing 
  flat, 
  plate 
  like 
  gills, 
  which 
  offer 
  greater 
  surface 
  for 
  

   contact 
  with 
  the 
  water; 
  

  

  2 
  In 
  developing 
  special 
  apparatus 
  for 
  the 
  independent 
  movement 
  of 
  the 
  

   gills, 
  or 
  for 
  causing 
  currents 
  of 
  water 
  to 
  flow 
  over 
  them. 
  

  

  It 
  is 
  the 
  smaller 
  species 
  that 
  are 
  gill-less. 
  The 
  extent 
  of 
  respiratory 
  

   surface 
  is 
  in 
  a 
  measure 
  proportioned, 
  i) 
  to 
  the 
  size 
  of 
  the 
  nymphs; 
  2) 
  to 
  

   the 
  condition 
  of 
  the 
  water, 
  whether 
  well 
  or 
  poorly 
  aerated. 
  

  

  It 
  is 
  because 
  of 
  the 
  limitations 
  on 
  the 
  respiratory 
  system 
  of 
  stone-fly 
  

   nymphs 
  that 
  they 
  are 
  so 
  restricted 
  in 
  their 
  aquatic 
  habitat. 
  

  

  As 
  to 
  the 
  food 
  of 
  the 
  stone 
  flies 
  there 
  have 
  been 
  a 
  number 
  of 
  guesses, 
  

   but 
  apparently 
  no 
  careful 
  and 
  continuous 
  observations 
  recorded. 
  It 
  is 
  

   supposed 
  that 
  the 
  nymphs 
  of 
  the 
  larger 
  species 
  eat 
  smaller 
  May 
  fly 
  

   nymphs, 
  and 
  soft-bodied 
  dipterous 
  larvae 
  associated 
  with 
  them 
  on 
  the 
  

   rocks; 
  but 
  Benjamin 
  D. 
  Walsh 
  has 
  said 
  that 
  perlid 
  nymphs 
  eat 
  decaying 
  

   vegetable 
  matter, 
  and 
  that 
  the 
  images 
  eat 
  nothing.2 
  Here, 
  then, 
  is 
  an 
  

   opportunity 
  for 
  some 
  careful 
  observer 
  to 
  replace 
  inferences 
  with 
  facts. 
  

  

  The 
  adult 
  stone 
  flies 
  may 
  be 
  collected 
  at 
  almost 
  any 
  season 
  of 
  the 
  

   year. 
  The 
  litde 
  black 
  capnias 
  emerge 
  in 
  winter. 
  They 
  live 
  mainly 
  in 
  

   small 
  brooks, 
  and 
  are 
  often 
  found 
  in 
  transformation 
  on 
  the 
  edge 
  of 
  the 
  

   ice. 
  Through 
  the 
  spring 
  months 
  the 
  dusky 
  and 
  grayish 
  little 
  nemouras 
  

  

  1 
  I 
  have 
  bred 
  a 
  species 
  of 
  Aeroneuria 
  in 
  some 
  numbers 
  from 
  nymphs 
  taken 
  from 
  rotting 
  oak 
  

   leaves 
  in 
  the 
  edge 
  of 
  an 
  ice 
  pond 
  at 
  Ithaca 
  N. 
  Y.; 
  but 
  the 
  water 
  about 
  the 
  bed 
  of 
  leaves 
  was 
  clear, 
  

   and 
  could 
  not 
  be 
  called 
  stagnant, 
  since 
  the 
  turbulent 
  Cascadilla 
  creek 
  flows 
  through 
  the 
  pond, 
  

  

  2 
  Practical 
  entomologist. 
  2:73. 
  

  

  