﻿406 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  The 
  plots 
  were 
  strikingly 
  unlike 
  in 
  that 
  there 
  were 
  fewer 
  species 
  in 
  the 
  

   second, 
  fewer 
  dragon 
  fly 
  and 
  May 
  fly 
  nynaphs 
  and 
  dipterous 
  larvae. 
  

   They 
  differed 
  farther 
  most 
  strikingly 
  in 
  the 
  kind 
  of 
  moUusks 
  present 
  : 
  the 
  

   Campeloma 
  decisumof 
  the 
  second 
  plot 
  was 
  absent 
  from 
  the 
  first 
  ; 
  

   it 
  is 
  common 
  in 
  the 
  pond 
  above. 
  The 
  long-horned 
  leaf 
  beetles, 
  D 
  o 
  - 
  

   n 
  a 
  c 
  i 
  a, 
  of 
  the 
  second 
  plot 
  were 
  a 
  special 
  feature 
  which 
  belonged 
  with 
  

   the 
  special 
  habitat 
  furnished 
  by 
  the 
  bur 
  reed 
  growth. 
  Two 
  photographs, 
  

   reproduced 
  in 
  plate 
  9, 
  show 
  these 
  insects 
  in 
  their 
  natural 
  positions 
  on 
  the 
  

   plant. 
  

  

  These 
  are 
  fragments 
  — 
  mere 
  fragments 
  — 
  of 
  real 
  knowledge 
  of 
  the 
  life 
  of 
  

   this 
  stream. 
  While 
  not 
  without 
  interest 
  in 
  themselves, 
  they 
  seem 
  to 
  me 
  

   chiefly 
  valuable 
  in 
  their 
  suggestiveness 
  of 
  possible 
  knowledge 
  to 
  be 
  gained 
  

   by 
  farther 
  appHcation 
  of 
  these 
  methods. 
  

  

  Count 
  of 
  dragon 
  fly 
  exuviae. 
  In 
  the 
  midst 
  of 
  the 
  hatchery 
  grounds 
  

   there 
  was 
  a 
  fish 
  pond, 
  made 
  by 
  impounding 
  the 
  creek, 
  with 
  its 
  eastern 
  

   side 
  boarded 
  up 
  to 
  a 
  hight 
  of 
  15 
  to 
  20 
  inches 
  above 
  the 
  level 
  of 
  the 
  

   water, 
  for 
  a 
  distance 
  of 
  perhaps 
  20 
  yards. 
  The 
  boards 
  were 
  rough, 
  and 
  

   suited 
  dragon 
  fly 
  nymphs 
  very 
  well 
  as 
  a 
  place 
  to 
  transform. 
  It 
  was 
  an 
  

   exceptionally 
  favorable 
  place 
  in 
  which 
  to 
  learn 
  something 
  of 
  the 
  numbers 
  

   of 
  dragon 
  flies 
  to 
  emerge 
  from 
  a 
  given 
  water 
  area; 
  for 
  the 
  cast 
  skins 
  

   were 
  all 
  left 
  in 
  plain 
  view. 
  The 
  other 
  bank 
  was 
  not 
  boarded, 
  and 
  while 
  

   the 
  cast 
  skins 
  appeared 
  to 
  be 
  about 
  as 
  common 
  there, 
  one 
  co^uld 
  not 
  

   be 
  sure 
  of 
  finding 
  all 
  of 
  them. 
  A 
  view 
  of 
  this 
  pond, 
  looking 
  up 
  stream, 
  

   is 
  presented 
  in 
  plate 
  6. 
  

  

  Conditions 
  here 
  were 
  right 
  for 
  determining 
  the 
  yield 
  of 
  this 
  strip 
  of 
  

   water 
  in 
  dragon 
  flies 
  of 
  those 
  species 
  whose 
  period 
  of 
  transformation 
  falls 
  

   entirely 
  within 
  the 
  last 
  three 
  weeks 
  of 
  June 
  at 
  Saranac 
  Inn. 
  I 
  do 
  not 
  

   say 
  half 
  the 
  yield, 
  because 
  it 
  seems 
  fair 
  to 
  presume 
  that 
  half 
  were 
  on 
  the 
  

   other 
  bank, 
  where 
  their 
  discovery 
  was 
  not 
  so 
  easy. 
  Nymphs 
  when 
  ready 
  

   to 
  transform 
  are 
  blind, 
  and 
  wander 
  about 
  till 
  they 
  find 
  a 
  bank, 
  showing 
  

   no 
  preference 
  as 
  to 
  which 
  bank 
  it 
  is. 
  These 
  time 
  limits 
  are 
  taken 
  be- 
  

   cause 
  they 
  are 
  the 
  only 
  narrow 
  ones 
  that 
  will 
  include 
  the 
  entire 
  trans- 
  

   formation 
  period 
  of 
  a 
  considerable 
  number 
  of 
  species. 
  

  

  I 
  found 
  quite 
  a 
  number 
  of 
  these 
  skins 
  already 
  clinging 
  to 
  the 
  boards 
  on 
  

   my 
  arrival 
  June 
  12, 
  for 
  the 
  season 
  for 
  transformation 
  for 
  some 
  of 
  these 
  

   species 
  was 
  already 
  at 
  hand. 
  It 
  appears 
  fair 
  to 
  assume, 
  however, 
  that 
  I 
  

   obtained 
  practically 
  all 
  the 
  skins 
  that 
  had 
  been 
  left 
  there, 
  because 
  they 
  

   had 
  apparently 
  not 
  been 
  disturbed 
  at 
  all 
  ; 
  they 
  stick 
  very 
  tightly, 
  so 
  that 
  

   moderate 
  winds 
  and 
  even 
  rain 
  do 
  not 
  quickly 
  dislodge 
  them. 
  The 
  weather 
  

   previous 
  to 
  my 
  arrival 
  had 
  been 
  clear 
  and 
  calm, 
  and 
  the 
  season 
  of 
  trans- 
  

  

  