﻿AQUATIC 
  INSECTS 
  IN 
  THE 
  ADIRONDACKS 
  543 
  

  

  shores 
  of 
  a 
  pond 
  at 
  Galesburg 
  111. 
  black 
  with 
  these 
  flies 
  about 
  the 
  begin- 
  

   ning 
  of 
  June. 
  

  

  Several 
  adults 
  were 
  taken 
  on 
  both 
  Little 
  Clear 
  and 
  Big 
  Clear 
  creeks, 
  

   during 
  the 
  latter 
  half 
  of 
  June. 
  Larvae 
  were 
  obtained 
  in 
  -small 
  numbers 
  

   from 
  Little 
  Clear 
  creek 
  on 
  the 
  hatchery 
  grounds. 
  No 
  attempt 
  was 
  made 
  

   to 
  rear 
  them. 
  I 
  have 
  reared 
  the 
  species 
  in 
  Ithaca 
  N. 
  Y. 
  in 
  1897. 
  Larvae 
  

   obtained 
  here 
  agree 
  entirely 
  with 
  others 
  from 
  Ithaca 
  and 
  from 
  Galesburg 
  

   III. 
  

  

  The 
  larvae 
  live 
  in 
  trashy 
  places 
  filled 
  with 
  aquatic 
  plants 
  in 
  the 
  borders 
  

   of 
  streams 
  and 
  ponds. 
  They 
  clamber 
  through 
  fallen 
  vegetation 
  with 
  

   great 
  agility, 
  and 
  push 
  their 
  way 
  readily 
  through 
  sediment 
  fallen 
  on 
  the 
  

   bottom. 
  In 
  an 
  aquarium, 
  and 
  probably 
  outside, 
  the 
  abdomen 
  maintains 
  

   an 
  undulating 
  motion, 
  the 
  long 
  tail 
  being 
  intermittently 
  lashed 
  up 
  and 
  

   down. 
  This 
  causes 
  a 
  swirl 
  in 
  the 
  water, 
  which 
  is 
  doubtless 
  useful 
  in 
  bring- 
  

   ing 
  a 
  fresh 
  supply 
  of 
  water 
  into 
  contact 
  with 
  the 
  lateral 
  filaments. 
  

  

  The 
  larvae, 
  when 
  fully 
  grown, 
  transform 
  in 
  moist 
  soil 
  at 
  some 
  little 
  

   distance 
  from 
  the 
  edge 
  of 
  the 
  water. 
  At 
  a 
  depth 
  of 
  several 
  inches 
  or 
  a 
  

   foot 
  or 
  more, 
  depending 
  on 
  the 
  character 
  of 
  the 
  soil, 
  an 
  oval 
  cell 
  is 
  

   formed 
  in 
  which 
  die 
  larva 
  curls 
  itself 
  up, 
  and 
  without 
  making 
  a 
  cocoon 
  

   becomes 
  a 
  pupa. 
  Two 
  or 
  three 
  weeks 
  after 
  the 
  making 
  of 
  the 
  pupal 
  cell 
  

   the 
  adult 
  fly 
  emerges. 
  

  

  Excellent 
  available 
  accounts 
  of 
  European 
  species 
  of 
  Sialis 
  are: 
  

  

  Pictet, 
  F. 
  J. 
  M6nioire 
  siir 
  le 
  genre 
  Sialis 
  Latreille, 
  etc. 
  Ann. 
  sci. 
  iiat. 
  (2) 
  

  

  1836. 
  5: 
  69-80, 
  1 
  colored 
  pi. 
  (life 
  history) 
  

   Nunney, 
  W. 
  H, 
  Development 
  of 
  the 
  alder 
  jEly. 
  Science 
  gossip, 
  n. 
  s. 
  1895 
  

  

  2 
  : 
  257-58. 
  

   Miall, 
  L. 
  C. 
  The 
  alder 
  fly. 
  Natural 
  history 
  of 
  aquatic 
  insects, 
  p. 
  273-8, 
  1895. 
  

  

  Larva 
  (PI. 
  29, 
  fig. 
  3) 
  Measures 
  in 
  length 
  22 
  mm, 
  including 
  a 
  

   tail 
  4 
  mm 
  long 
  ; 
  width 
  2.3 
  mm. 
  Head 
  and 
  thorax 
  of 
  equal 
  width, 
  

   abdomen 
  very 
  slowly 
  tapering. 
  

  

  Color 
  yellowish, 
  darker 
  on 
  the 
  abdomen; 
  a 
  middorsal 
  line 
  of 
  brown 
  

   extending 
  from 
  the 
  middle 
  of 
  the 
  head 
  to 
  the 
  base 
  of 
  the 
  abdomen, 
  in- 
  

   terrupted 
  on 
  the 
  middle 
  of 
  the 
  prothorax 
  ; 
  an 
  arrow-shaped 
  mark 
  on 
  the 
  

   frons, 
  and 
  a 
  brown 
  line 
  extending 
  obhquely 
  inward 
  from 
  the 
  hind 
  angles 
  

   of 
  the 
  head. 
  Sides 
  of 
  thorax 
  mottled 
  with 
  yellow 
  and 
  brown. 
  Abdomen 
  

   brownish 
  or 
  purplish 
  with 
  paler 
  sutures 
  and 
  a 
  pair 
  of 
  submedian, 
  dorsal 
  

   ( 
  ) 
  -marks 
  on 
  the 
  middle 
  abdominal 
  segments. 
  

  

  Head 
  depressed, 
  subquadrangular, 
  with 
  rounded 
  angles, 
  and 
  pro- 
  

   jecting 
  mouth 
  parts; 
  prothorax 
  subquadrangular, 
  as 
  large 
  as 
  the 
  head, 
  

   and 
  about 
  as 
  large 
  as 
  the 
  two 
  succeeding 
  segments 
  of 
  the 
  thorax 
  taken 
  

   together. 
  

  

  Abdominal 
  segments 
  4-7 
  of 
  about 
  equal 
  length, 
  3, 
  2 
  and 
  i, 
  succes- 
  

   sively, 
  each 
  a 
  Httle 
  shorter; 
  segment 
  9 
  a 
  little 
  shorter 
  than 
  8; 
  10 
  drawn 
  

   out 
  into 
  the 
  tapering, 
  lashlike 
  filament 
  4 
  mm 
  long 
  ; 
  the 
  filament 
  marked 
  

   with 
  black 
  at 
  two 
  thirds 
  its 
  length 
  and 
  laterally 
  fringed 
  with 
  yellowish 
  

  

  