﻿AQUATIC 
  INSECTS 
  IN 
  THE 
  ADIRONDACKS 
  42I 
  

  

  were 
  snapped 
  up 
  eagerly 
  by 
  the 
  trout. 
  The 
  membrane 
  of 
  the 
  wings 
  of 
  

   the 
  imago 
  is 
  in 
  this 
  species 
  finely 
  iridescent. 
  

  

  Nymph. 
  PI. 
  15, 
  fig. 
  16 
  Length 
  of 
  body 
  10 
  mm; 
  setae, 
  male 
  12, 
  

   female 
  15 
  additional; 
  abdomen, 
  male 
  6.25, 
  female 
  7. 
  

  

  Body 
  flat; 
  lateral 
  margins 
  of 
  the 
  head 
  and 
  prothorax 
  thin, 
  sharp 
  

   edged, 
  flaring, 
  that 
  of 
  the 
  head 
  projecting 
  distinctly 
  beneath 
  the 
  eyes, 
  

   antennae 
  reaching 
  the 
  tips 
  of 
  the 
  extended 
  fore 
  femora; 
  all 
  femora 
  

   flattened, 
  sharp 
  edged, 
  edges 
  very 
  convex 
  and 
  fringed 
  with 
  hairs. 
  

  

  Color 
  yellowish 
  or 
  greenish 
  brown, 
  mottled, 
  paler 
  below, 
  and 
  dorsally 
  

   marked 
  with 
  paler 
  spots 
  as 
  follows 
  : 
  an 
  inverted, 
  mushroom-shaped 
  spot 
  

   before 
  the 
  middle 
  ocellus, 
  a 
  triangular 
  patch 
  between 
  each 
  reniform, 
  

   lateral 
  ocellus 
  and 
  the 
  eye, 
  a 
  transverse 
  band 
  at 
  the 
  rear 
  of 
  the 
  head; 
  

   an 
  oblique 
  band 
  each 
  side 
  of 
  the 
  prothorax, 
  a 
  large 
  lateral 
  spot 
  each 
  side 
  

   of 
  each 
  of 
  the 
  intermediate 
  abdominal 
  segments 
  with 
  a 
  black 
  mark 
  at 
  

   its 
  hind 
  margin. 
  The 
  femora 
  and 
  tibiae 
  show 
  very 
  indistinct 
  transverse 
  

   banding 
  of 
  color. 
  

  

  Abdomen 
  with 
  sharply 
  toothed 
  posterolateral 
  angles 
  on 
  its 
  hindmost 
  

   segments, 
  the 
  tooth 
  largest 
  on 
  the 
  eighth 
  segment, 
  where 
  it 
  surpasses 
  the 
  

   middle 
  of 
  the 
  ninth 
  segment, 
  smaller 
  on 
  the 
  seventh 
  and 
  ninth, 
  and 
  a 
  

   mere 
  sharp 
  angle 
  on 
  the 
  sixth 
  segment. 
  Setae 
  sparsely 
  fringed 
  with 
  hairs 
  

   for 
  a 
  third 
  of 
  their 
  length. 
  

  

  Gills 
  present 
  on 
  segments 
  1-7, 
  similar 
  on 
  1-6, 
  though 
  becoming 
  

   smaller 
  posteriorly. 
  Anterior 
  gills 
  double, 
  the 
  anterior 
  leaf 
  thickened, 
  

   trapezoidal 
  with 
  the 
  angles 
  all 
  obtuse, 
  a 
  sparse 
  fringe 
  of 
  slender 
  hairs 
  

   around 
  the 
  distal 
  half 
  of 
  its 
  border, 
  a 
  strong 
  oblique, 
  longitudinal 
  ridge 
  

   on 
  its 
  anterior 
  face 
  near 
  its 
  ventral 
  edge 
  ; 
  posterior 
  leaf 
  thin 
  and 
  deli- 
  

   cate, 
  covered 
  by 
  the 
  anterior, 
  smaller 
  than 
  the 
  anterior, 
  cordate 
  

   triangular 
  in 
  general 
  outline, 
  cut 
  into 
  a 
  peripheral 
  fringe 
  of 
  long 
  

   respiratory 
  filaments 
  which 
  are 
  once 
  or 
  twice 
  forked 
  or 
  simple, 
  the 
  fringe 
  

   being 
  as 
  long 
  as 
  the 
  body 
  of 
  the 
  leaf. 
  Gill 
  of 
  the 
  seventh 
  segment 
  

   simple 
  (corresponding 
  to 
  the 
  anterior 
  leaf 
  only), 
  lanceolate, 
  fringed 
  

   along 
  its 
  entire 
  margin, 
  its 
  apex 
  surpassing 
  the 
  lateral 
  tooth 
  of 
  the 
  

   eighth 
  abdominal 
  segment. 
  

  

  This 
  species 
  is 
  known 
  from 
  Rock 
  Island 
  III., 
  Maryland, 
  New 
  York 
  

  

  and 
  Quebec. 
  

  

  There 
  is 
  in 
  the 
  Museum 
  of 
  comparative 
  zoology 
  a 
  specimen 
  of 
  another 
  

   species 
  labeled 
  "Adirondacks, 
  New 
  York, 
  Aug. 
  1872" 
  in 
  Dr 
  Hagen's 
  

   handwriting, 
  which 
  agrees 
  entirely 
  with 
  other 
  specimens 
  in 
  the 
  same 
  

   museum 
  bearing 
  the 
  name 
  Heptagenia 
  vicaria 
  Walker. 
  

  

  Baetis 
  pygmea 
  Hagen 
  

  

  Plate 
  15, 
  figures 
  13, 
  14 
  

  

  1861 
  Cloe 
  pygmea 
  Hagen, 
  Synopsis 
  Neur. 
  N. 
  Am. 
  p. 
  54 
  (original 
  descrip- 
  

   tion) 
  

  

  1863 
  Cloe 
  pygmaea 
  Hagen, 
  Ent. 
  soc. 
  Phil. 
  Proc. 
  2 
  : 
  178-79 
  (notes, 
  "It 
  is 
  

   the 
  smallest 
  ephemerous 
  species 
  known.'') 
  

  

  1871 
  Baetis 
  pygmaeus 
  Eaton, 
  Ent. 
  soc. 
  Lond. 
  Trans, 
  p. 
  122 
  (original 
  

   description, 
  repeated 
  in 
  Latin) 
  

  

  