﻿AQUATIC 
  INSECTS 
  IN 
  THE 
  ADIRONDACKS 
  489^ 
  

  

  from 
  the 
  grown 
  nymph 
  in 
  this 
  respect 
  is 
  sometimes 
  (but 
  very 
  rarely) 
  

   true. 
  Labium 
  with 
  four 
  (less 
  often 
  five) 
  lateral 
  setae, 
  and 
  four 
  larger 
  

   mental 
  setae 
  each 
  side, 
  with 
  one 
  or 
  two 
  lesser 
  ones 
  near 
  the 
  median 
  line* 
  

   Thorax 
  with 
  broad 
  sterna. 
  

  

  Abdomen 
  depressed, 
  triquetral 
  ; 
  dorsal 
  hooks 
  large, 
  cultriform, 
  in 
  a 
  

   very 
  regular 
  series, 
  on 
  segments 
  2-9; 
  lateral 
  spines 
  on 
  segments 
  8 
  and 
  9, 
  

   those 
  of 
  the 
  ninth 
  segment 
  surpassing 
  the 
  level 
  of 
  the 
  tips 
  of 
  the 
  append- 
  

   ages; 
  superior 
  appendage 
  very 
  nearly 
  as 
  long 
  as 
  the 
  inferiors, 
  laterals 
  a 
  

   little 
  more 
  than 
  half 
  as 
  long 
  as 
  the 
  inferiors. 
  

  

  There 
  are 
  two 
  indistinct 
  and 
  interrupted 
  bands 
  of 
  brownish 
  markings, 
  

   extending 
  from 
  the 
  hind 
  angles 
  of 
  the 
  head 
  to 
  the 
  bases 
  of 
  the 
  spines 
  on 
  

   the 
  ninth 
  abdominal 
  segment, 
  and 
  there 
  are 
  darker 
  rings 
  on 
  tibiae 
  and 
  

   femora, 
  discoverable 
  specially 
  after 
  molting. 
  

  

  This 
  species 
  was 
  seen 
  but 
  a 
  few 
  times 
  at 
  Saranac 
  Inn, 
  and 
  no 
  speci- 
  

   mens 
  were 
  taken 
  either 
  as 
  nymphs 
  or 
  images. 
  It 
  is 
  not 
  uncommon 
  in 
  

   other 
  places 
  in 
  the 
  state, 
  and 
  will 
  probably 
  be 
  found 
  quite 
  generally 
  dis- 
  

   tributed 
  when 
  proper 
  search 
  is 
  made 
  for 
  it. 
  

  

  TETRAGONEURIA 
  

  

  This 
  North 
  American 
  genus 
  is 
  one 
  of 
  the 
  most 
  important, 
  most 
  

   generally 
  distributed, 
  and 
  most 
  common 
  in 
  the 
  subfamily. 
  The 
  images 
  

   are 
  somewhat 
  scarce 
  in 
  collections, 
  but 
  they 
  are 
  by 
  no 
  means 
  so 
  in 
  

   nature. 
  Because 
  of 
  their 
  superb 
  aerial 
  powers 
  they 
  are 
  not 
  often 
  taken 
  

   in 
  flight. 
  They 
  depart 
  widely 
  from 
  the 
  regular 
  haunts 
  of 
  the 
  less 
  active 
  

   species 
  while 
  foraging, 
  and 
  thus 
  often 
  escape 
  the 
  specialist 
  who 
  is 
  collect- 
  

   ing 
  for 
  dragon 
  flies 
  in 
  particular. 
  The 
  roving 
  habits 
  of 
  the 
  imagos 
  

   account 
  sufficiently 
  for 
  the 
  wide 
  distribution 
  of 
  most 
  of 
  our 
  species. 
  

  

  About 
  an 
  Illinois 
  pond 
  in 
  which 
  Epicordulia 
  princeps 
  and 
  

   Tetragoneuria 
  cynosura 
  were 
  the 
  only 
  Cordulinae 
  present, 
  I 
  

   have 
  watched 
  day 
  after 
  day 
  the 
  little 
  Tetragoneuria 
  chasing 
  the 
  big; 
  

   Epicordulia 
  about 
  in 
  air, 
  much 
  as 
  a 
  kingbird 
  chases 
  and 
  harasses 
  a 
  

   crow, 
  surpassing 
  by 
  its 
  swiftness 
  and 
  by 
  its 
  ability 
  to 
  make 
  quick 
  

   turns 
  in 
  air. 
  

  

  Nymphs 
  of 
  this 
  genus 
  may 
  be 
  found 
  in 
  almost 
  any 
  pond; 
  they 
  are 
  

   often 
  found 
  in 
  enormous 
  numbers. 
  By 
  far 
  the 
  easiest 
  v/ay 
  to 
  get 
  imagos 
  

   is 
  to 
  capture 
  well 
  grown 
  nymphs 
  and 
  rear 
  them. 
  

  

  Nymphs 
  of 
  this 
  genus 
  agree 
  so 
  closely 
  that 
  I 
  give 
  here 
  a 
  general 
  

  

  account 
  of 
  them, 
  which, 
  for 
  specific 
  descriptions 
  will 
  only 
  need 
  to 
  be 
  

  

  supplemented 
  by 
  the 
  specific 
  characters 
  stated 
  in 
  the 
  following 
  table; 
  

  

  the 
  differences 
  therein 
  stated 
  are 
  the' 
  only 
  differences 
  I 
  know 
  between 
  the 
  

  

  species. 
  

  

  The 
  nymphs 
  are 
  trim 
  and 
  smooth, 
  with 
  depressed 
  abdomen 
  and 
  long 
  

   lateral 
  spines. 
  The 
  general 
  color 
  is 
  greenish 
  or 
  yellowish, 
  with 
  a 
  

  

  