﻿AQUATIC 
  INSECTS 
  IN 
  THE 
  ADIRONDACKS 
  417 
  

  

  tnoniliform 
  ; 
  not 
  close 
  set 
  cylindric 
  and 
  tapering 
  as 
  in 
  the 
  more 
  typical 
  

   Perlidae. 
  Median 
  ocellus 
  cleariy 
  double! 
  

  

  Body 
  slender, 
  with 
  sides 
  neariy 
  parallel. 
  The 
  prothorax 
  narrower 
  

   than 
  the 
  head, 
  regularly 
  quadrangular, 
  with 
  straight 
  sides 
  and 
  ends, 
  and 
  

   with 
  angles 
  all 
  a 
  Httle 
  rounded 
  ; 
  a 
  faint 
  median 
  raised 
  line 
  and 
  on 
  either 
  

   side 
  of 
  it 
  a 
  faint 
  raised 
  circle 
  covering 
  nearly 
  half 
  of 
  the 
  prothoracic 
  

   dorsum. 
  

  

  Color 
  brown, 
  becoming 
  yellowish 
  on 
  legs 
  and 
  sutures. 
  Wings 
  smoky 
  

   hyaline 
  with 
  brown 
  veins 
  {see 
  pi. 
  15, 
  fig. 
  12). 
  

  

  On 
  the 
  dorsum 
  of 
  the 
  abdomen 
  in 
  the 
  male 
  there 
  is 
  a 
  conspicuous 
  

   prominence 
  on 
  the 
  seventh 
  segment 
  

   which 
  rises 
  to 
  a 
  hight 
  equal 
  to 
  one 
  

   fifth 
  of 
  the 
  thickness 
  of 
  the 
  abdomen 
  

   (fig. 
  4^). 
  

  

  Nymph. 
  Fully 
  grown, 
  measures 
  

   12 
  mm 
  in 
  length 
  of 
  head 
  and 
  body; 
  

   abdomen 
  alone 
  4.5 
  mm; 
  antenna 
  

   4.5 
  mm; 
  abdominal 
  setae 
  4.5 
  mm. 
  

   Width 
  of 
  head 
  .o 
  mm. 
  

  

  -P,, 
  ., 
  -^ 
  , 
  ,,, 
  .J 
  Fig. 
  5 
  Wings 
  of 
  Leuctra 
  teaella 
  

  

  JBody 
  With 
  nearly 
  parallel 
  sides. 
  

   Head 
  as 
  wide 
  as 
  the 
  prothorax; 
  mesothorax 
  a 
  little 
  wider; 
  abdomen 
  a 
  

   little 
  narrower. 
  

  

  Color 
  nearly 
  uniform 
  yellowish 
  fulvous, 
  pale 
  below 
  and 
  on 
  sutures, 
  

   antennae 
  and 
  setae. 
  Legs 
  pale 
  yellow. 
  Eyes 
  blackish 
  ; 
  ocelH 
  brownish, 
  

   with 
  a 
  faint 
  wash 
  of 
  brown 
  between 
  the^jposterior 
  pair. 
  

  

  No 
  tracheal 
  gills. 
  

  

  Little 
  Clear 
  creek 
  at 
  Saranac 
  Inn 
  N. 
  Y. 
  June 
  21, 
  24, 
  26, 
  28, 
  July 
  31 
  

   and 
  Aug. 
  2, 
  1900. 
  Not 
  common. 
  

  

  The 
  two 
  stone 
  flies 
  discussed 
  above 
  fall 
  in 
  separate 
  divisions 
  of 
  the 
  

   family, 
  which 
  I 
  regard 
  as 
  subfamiUes, 
  distinguishable 
  by 
  the 
  following 
  

   characteristics. 
  

  

  1 
  Perlinae. 
  Imago. 
  The 
  median 
  vein 
  hardly 
  fused 
  with 
  the 
  radius 
  

   at 
  the 
  base, 
  but 
  running 
  close 
  beside 
  it, 
  and 
  bending 
  away 
  from 
  it 
  very 
  

   gradually, 
  not 
  forming 
  a 
  distinct 
  arculus. 
  

  

  Nymph. 
  Flat 
  body, 
  flattened 
  femora 
  ciliate 
  on 
  the 
  sharp 
  and 
  convex 
  

   margins, 
  and 
  with 
  tapering 
  abdomen. 
  Tracheal 
  gills, 
  when 
  developed, 
  

   consisting 
  of 
  tufts 
  of 
  filaments. 
  

  

  This 
  subfamily 
  includes 
  the 
  two 
  tribes, 
  Pteronarcini 
  and 
  Perlini 
  of 
  

   Banks.i 
  

  

  2 
  Nemourinae. 
  Imago. 
  The 
  median 
  vein 
  fused 
  with 
  the 
  radius 
  at 
  

   the 
  base, 
  then 
  bending 
  sharply 
  away 
  from 
  it 
  to 
  meet 
  the 
  cross 
  vein, 
  with 
  

   which 
  it 
  forms 
  a 
  distinct 
  arculus. 
  

  

  Nymph. 
  More 
  cylindric 
  body; 
  femora 
  not 
  flattened 
  or 
  sharp 
  edged; 
  

   abdomen 
  with 
  nearly 
  parallel 
  sides. 
  Tracheal 
  gills 
  when 
  developed 
  

  

  1 
  Am. 
  ent. 
  soc. 
  Traus. 
  1900. 
  24 
  : 
  240. 
  

  

  