﻿AQUATIC 
  INSECTS 
  IN 
  THE 
  ADIRONDACKS 
  

  

  473 
  

  

  Labium 
  short 
  and 
  stout, 
  median 
  lobe 
  with 
  a 
  narrow 
  median 
  cleft 
  and 
  

   denticulate 
  margin 
  ; 
  lateral 
  lobes 
  truncate 
  on 
  end, 
  scarcely 
  denticulate 
  : 
  

   no 
  raptorial 
  setae. 
  

  

  Legs 
  stout, 
  with 
  prominent, 
  twisted, 
  hair-fringed, 
  longitudinal 
  carinae; 
  

   tarsi 
  3-3-3 
  jointed. 
  

  

  Wing 
  cases 
  laid 
  parallel 
  along 
  the 
  back, 
  their 
  apices 
  reaching 
  the 
  mid- 
  

   dle 
  of 
  the 
  fifth 
  segment. 
  

  

  Abdomen 
  tapering 
  beyond 
  the 
  fifth 
  segment 
  with 
  thin 
  flaring 
  lateral 
  

   margins 
  showing 
  on 
  each 
  of 
  segments 
  4-9 
  an 
  angle 
  at 
  the 
  middle 
  and 
  a 
  

   flat 
  tooth 
  at 
  the 
  apex, 
  and 
  with 
  a 
  dorsal 
  row 
  of 
  hairy 
  tubercles 
  on 
  seg- 
  

   ments 
  5-9, 
  parallel 
  to 
  the 
  lateral 
  margin 
  but 
  nearer 
  the 
  median 
  line 
  : 
  ap- 
  

   pendages 
  obtuse, 
  the 
  superior 
  with 
  a 
  broad, 
  shallow, 
  apical 
  emargination. 
  

  

  The 
  eggs 
  are 
  deposited 
  in 
  wet, 
  boggy 
  places, 
  when 
  there 
  is 
  hardly 
  any 
  

  

  water 
  standing, 
  and 
  the 
  nymph 
  lives 
  in 
  the 
  mud 
  in 
  such 
  places. 
  

  

  Subfamily 
  cordulegasterinae 
  

   A 
  small 
  group 
  of 
  large 
  species, 
  inhabiting 
  mainly 
  clear 
  streams 
  that 
  

   flow 
  through 
  upland 
  marshes, 
  spring 
  bogs, 
  etc. 
  The 
  imagos 
  are 
  strong 
  

   of 
  flight, 
  and 
  are 
  oftenest 
  seen 
  cours- 
  

   ing 
  back 
  and 
  forth 
  over 
  some 
  small 
  

   stream, 
  flying 
  on 
  a 
  regular 
  beat, 
  and 
  

   passing 
  and 
  repassing 
  the 
  same 
  

   point 
  at 
  intervals 
  of 
  a 
  few 
  minutes. 
  

   The 
  collector 
  may 
  take 
  advantage 
  

   of 
  this 
  habit, 
  and 
  so 
  station 
  himself 
  

   that 
  he 
  may 
  reach 
  the 
  specimen 
  as 
  

   it 
  passes, 
  and 
  capture 
  it^ 
  if 
  dextrous 
  

   with 
  a 
  net. 
  

  

  The 
  nymphs 
  live 
  on 
  the 
  bottom 
  

   in 
  shallow 
  water, 
  buried 
  in 
  clean 
  

   sand 
  or 
  in 
  vegetable 
  silt. 
  Though 
  

   buried 
  they 
  do 
  not 
  burrow, 
  but 
  descend 
  by 
  raking 
  the 
  sand 
  from 
  beneath 
  

   them 
  by 
  sweeping, 
  lateral 
  movements 
  of 
  the 
  legs. 
  When 
  deep 
  enough, 
  

   they 
  kick 
  the 
  sand 
  up 
  over 
  the 
  back 
  till 
  only 
  the 
  elevated 
  tips 
  of 
  the 
  eyes 
  

   and 
  the 
  respiratory 
  aperture 
  at 
  the 
  tip 
  of 
  the 
  abdomen 
  are 
  exposed. 
  By 
  

   placing 
  a 
  Hve 
  nymph 
  in 
  a 
  dish 
  of 
  sand 
  and 
  water 
  and 
  watching, 
  its 
  

   method 
  may 
  be 
  observed 
  in 
  a 
  very 
  few 
  minutes. 
  The 
  whole 
  comical 
  

   performance 
  reminds 
  one 
  strongly 
  of 
  the 
  descent 
  of 
  an 
  old 
  hen 
  in 
  a 
  

   dustbath. 
  

  

  Once 
  adjusted 
  in 
  the 
  sand, 
  a 
  nymph 
  (unless 
  food 
  tempts) 
  remains 
  

   motionless 
  a 
  very 
  long 
  time. 
  In 
  a 
  dish 
  of 
  sand 
  on 
  my 
  table, 
  I 
  have 
  had 
  a 
  

   nymph 
  remain 
  without 
  change 
  of 
  position 
  for 
  weeks, 
  no 
  food 
  being 
  

   offered 
  it. 
  Let 
  any 
  little 
  insect 
  walk 
  or 
  swim 
  near 
  the 
  nymph's 
  head^ 
  

  

  Fig. 
  15 
  Tachopteryx 
  thoreyl 
  Selys; 
  a 
  

   bium 
  and 
  b 
  antenna 
  of 
  a 
  female 
  nymph 
  ( 
  Mr 
  

   Williamson's 
  type 
  ) 
  

  

  