﻿AQUATIC 
  INSECTS 
  IN 
  THE 
  ADIRONDACKS 
  475 
  

  

  hh 
  Face 
  blackish 
  erroneous 
  

  

  aaa 
  Abdomen 
  with 
  lateral 
  spots 
  

  

  c 
  Abdomen 
  65 
  mm 
  or 
  more 
  in 
  length 
  (southern') 
  fasciatus 
  

  

  cc 
  Abdomen 
  less 
  than 
  60 
  mm 
  in 
  length 
  

  

  d 
  Spots 
  single 
  on 
  sides 
  of 
  abdominal 
  segments 
  diastatops 
  

  

  dd 
  With 
  large, 
  separate, 
  median 
  and 
  apical 
  spots 
  on 
  sides 
  of 
  middle 
  abdom- 
  

   inal 
  segments 
  maculatus 
  

  

  As 
  to 
  the 
  nymphs, 
  few 
  of 
  them 
  are 
  known. 
  Cabot^ 
  has 
  figured 
  and 
  

   described 
  as 
  C. 
  sayi 
  (supposition) 
  nymphs, 
  which, 
  later, 
  Hagen^ 
  has 
  

   referred 
  to 
  C. 
  diastatops 
  (supposition). 
  These 
  nymphs 
  were 
  from 
  

   Maine, 
  Massachusetts, 
  Maryland 
  and 
  Virginia. 
  It 
  is 
  very 
  doubtful 
  

   whether 
  C. 
  sayi 
  occurs 
  so 
  far 
  norrh 
  as 
  Massachusetts: 
  owing 
  to 
  con- 
  

   fusion 
  of 
  species, 
  published 
  records 
  of 
  distribution 
  of 
  our 
  species 
  of 
  

   Cordulegaster 
  need 
  sifting. 
  I 
  have 
  bred 
  C. 
  diastatops 
  at 
  Ithaca, 
  

   and 
  my 
  nymphs 
  agree 
  with 
  Hagen's 
  description, 
  and 
  thus 
  confirm 
  his 
  

   supposition. 
  In 
  the 
  above 
  cited 
  paper 
  Dr 
  Hagen 
  also 
  published 
  brief 
  

   descriptive 
  notes 
  on 
  two 
  other 
  Cordulegaster 
  nymphs 
  which 
  he 
  

   referred 
  by 
  supposition 
  to 
  C. 
  dorsalis 
  (of 
  the 
  Pacific 
  slope) 
  and 
  C. 
  

   obliquus 
  (the 
  latter 
  one, 
  a 
  single 
  imperfect 
  specimen 
  from 
  Texas). 
  

   This 
  is 
  all 
  that 
  has 
  been 
  published 
  concerning 
  the 
  nymphs 
  of 
  American 
  

   species 
  of 
  this 
  genus. 
  

  

  I 
  describe 
  below 
  nymphs 
  of 
  C. 
  diastatops 
  (raised) 
  and 
  C. 
  

   maculatus 
  (supposition), 
  and 
  in 
  order 
  to 
  avoid 
  repetitions, 
  I 
  will 
  give 
  

   herewith 
  a 
  general 
  statement 
  of 
  the 
  characters 
  of 
  nymphs 
  of 
  the 
  genus 
  : 
  

   they 
  are 
  all 
  very 
  much 
  alike. 
  

  

  Nymphs 
  of 
  this 
  genus 
  agree 
  in 
  the 
  following 
  points 
  : 
  the 
  body 
  is 
  stout, 
  

   rough, 
  hairy, 
  cylindric, 
  tapering 
  beyond 
  the 
  middle 
  of 
  the 
  abdomen 
  to 
  a 
  

   pointed 
  apex, 
  the 
  longitudinal 
  axis 
  upcurved 
  at 
  both 
  ends, 
  the 
  tips 
  of 
  the 
  

   eyes 
  and 
  the 
  abdominal 
  appendages 
  being 
  the 
  highest 
  points. 
  The 
  

   antennae 
  are 
  seven-jointed, 
  slender. 
  The 
  eyes 
  cap 
  the 
  angular 
  antero- 
  

   lateral 
  prominence 
  of 
  the 
  head 
  and 
  extend 
  a 
  pair 
  of 
  sharp 
  points 
  inter- 
  

   nally 
  on 
  the 
  vertex 
  from 
  their 
  hind 
  angles. 
  Hind 
  angles 
  of 
  the 
  head 
  

   rounded, 
  the 
  hind 
  margin 
  not 
  obviously 
  concave 
  posteriorly. 
  The 
  

   labium 
  is 
  very 
  large, 
  extending 
  posteriorly 
  between 
  the 
  bases 
  of 
  the 
  mid- 
  

   dle 
  legs, 
  its 
  dilated, 
  spoon-shaped 
  anterior 
  end 
  covering 
  the 
  face 
  up 
  to 
  

   the 
  antennae, 
  and 
  meeting 
  above 
  a 
  convex 
  frontal 
  prominence, 
  whose 
  

   margin 
  is 
  fringed 
  with 
  sensory 
  hairs. 
  The 
  mentum 
  is 
  triangularly 
  

   widened 
  beyond 
  the 
  middle; 
  its 
  median 
  lobe 
  is 
  produced 
  in 
  a 
  median 
  

   tooth 
  which 
  is 
  bifid 
  on 
  the 
  median 
  line; 
  its 
  lateral 
  lobes 
  are 
  broad, 
  tri- 
  

   angular, 
  concave, 
  and 
  bear 
  a 
  row 
  of 
  short 
  raptorial 
  setae 
  just 
  within 
  the 
  

   external 
  margin, 
  a 
  stouter, 
  but 
  not 
  longer 
  movable 
  hook 
  at 
  the 
  end 
  of 
  

   this 
  row, 
  and 
  a 
  series 
  of 
  coarse, 
  irregular 
  interlocking 
  teeth 
  on 
  the 
  distal 
  

   margin. 
  

  

  1 
  Immature 
  state 
  of 
  the 
  Odonata. 
  1872. 
  pt 
  1, 
  p. 
  13, 
  pi. 
  3, 
  fig. 
  2. 
  

  

  2 
  Monograph 
  of 
  the 
  earlier 
  stages 
  of 
  the 
  Odonata, 
  Am. 
  ent. 
  soe. 
  Trans. 
  1885. 
  p. 
  290. 
  

  

  