﻿AQUATIC 
  INSECTS 
  IN 
  THE 
  ADIRONDACKS 
  

  

  495 
  

  

  Tetragoneuria 
  spinosa 
  Hagen 
  

  

  1878 
  Tetragoneuria 
  spinosa 
  Hagen, 
  Acad. 
  Belg. 
  (2) 
  Bui. 
  45 
  : 
  188 
  

  

  This 
  species 
  was 
  less 
  abundant 
  at 
  Saranac 
  Inn 
  than 
  the 
  others 
  of 
  the 
  

   genus 
  mentioned 
  as 
  occurring 
  there 
  ; 
  but 
  I 
  captured 
  at 
  random 
  a 
  number 
  

   of 
  specimens 
  of 
  both 
  sexes. 
  The 
  female 
  shown 
  in 
  pi. 
  22, 
  fig. 
  2, 
  exhibits 
  

   a 
  singular 
  type 
  of 
  coloration 
  for 
  this 
  genus. 
  The 
  wings 
  were 
  of 
  a 
  rich 
  fla- 
  

   vescent 
  brown, 
  with 
  spots 
  of 
  black 
  on 
  a 
  number 
  of 
  the 
  antenodal 
  cross 
  

   veins. 
  This 
  specimen 
  I 
  captured 
  among 
  the 
  wild 
  raspberry 
  bushes 
  

   near 
  the 
  house 
  of 
  the 
  station 
  agent 
  at 
  dusk, 
  June 
  27. 
  

  

  Owing 
  to 
  the 
  striking 
  difference 
  between 
  the 
  male 
  appendages 
  in 
  this 
  

   and 
  the 
  other 
  species 
  of 
  the 
  genus, 
  there 
  is 
  probably 
  no 
  need 
  here 
  of 
  a 
  

   new 
  description, 
  notwithstanding 
  that 
  the 
  original 
  one 
  in 
  French 
  seems 
  

   as 
  yet 
  to 
  be 
  the 
  only 
  one, 
  and 
  it 
  is 
  not 
  generally 
  accessible 
  in 
  this 
  

   country. 
  

  

  HELOCORDULIA 
  gCn. 
  nOV. 
  

  

  The 
  two 
  species 
  constituting 
  this 
  genus, 
  C. 
  uhleri 
  Selys 
  and 
  

   C. 
  s 
  e 
  1 
  y 
  s 
  i 
  Hagen, 
  have 
  been 
  included 
  hitherto 
  in 
  the 
  genus 
  

   Neurocordulia. 
  There 
  is 
  hardly 
  another 
  genus 
  within 
  the 
  corduHne 
  

   series 
  as 
  here 
  restricted, 
  with 
  which 
  these 
  have 
  less 
  affinity. 
  A 
  tabular 
  

   statement 
  of 
  the 
  differences 
  between 
  Helocordulia 
  and 
  N 
  e 
  u 
  r 
  o 
  - 
  

   c 
  o 
  r 
  d 
  u 
  1 
  i 
  a 
  (as 
  here 
  restricted) 
  with 
  respect 
  to 
  wing 
  venation 
  will 
  show 
  

   the 
  great 
  discrepances 
  for 
  a 
  single 
  organ 
  — 
  the 
  only 
  one 
  I 
  have 
  critically 
  

   studied. 
  

  

  CHARACTER 
  

  

  NEUROCORDULIA 
  

  

  HELOCOBDULIA 
  

  

  Veins 
  M4 
  and 
  Cui 
  

  

  divergent 
  apically 
  with 
  

   the 
  cell 
  rows 
  between 
  

   increasing 
  from 
  2 
  to 
  5 
  

  

  convergent 
  apically 
  with 
  

   but 
  two 
  cell 
  rows 
  be- 
  

   tween 
  

  

  Stigma 
  

  

  broad 
  and 
  slightly 
  ob- 
  

   lique 
  

  

  narrow 
  and 
  very 
  oblique 
  

   at 
  its 
  ends 
  

  

  Antenodals 
  of 
  hind 
  wing 
  

  

  five 
  

  

  six 
  

  

  Triangle 
  of 
  fore 
  wing 
  

  

  of 
  three 
  cells 
  

  

  of 
  two 
  cells 
  

  

  Triangle 
  of 
  hind 
  wing 
  

  

  of 
  two 
  cells 
  

  

  open 
  ; 
  no 
  cross 
  vein 
  

  

  Apex 
  of 
  anal 
  loop 
  

  

  with 
  a 
  long 
  posterior 
  

   angle, 
  and 
  at 
  least 
  five 
  

   cells 
  resting 
  against 
  

   the 
  distal 
  margin 
  

  

  squarely 
  truncate 
  or 
  near- 
  

   ly 
  so, 
  with 
  but 
  three 
  

   cells 
  on 
  the 
  distal 
  end 
  

  

  