﻿AQUATIC 
  INSECTS 
  IN 
  THE 
  ADIRONDACKS 
  561 
  

  

  Order 
  TRICHOPTERA 
  

   Caddis 
  flies 
  

  

  BY 
  CORNELIUS 
  BETTEN 
  

  

  Insects 
  of 
  this 
  order 
  were 
  found 
  to 
  be 
  very 
  abundant 
  at 
  Saranac 
  Inn. 
  

   Larvae 
  and 
  pupae 
  were 
  very 
  common 
  in 
  Little 
  Clear 
  creek 
  and 
  along 
  

   the 
  edges 
  of 
  the 
  lakes 
  and 
  ponds 
  of 
  the 
  vicinity, 
  while 
  adults 
  were 
  taken 
  

   in 
  great 
  numbers 
  by 
  the 
  trap 
  lanterns. 
  Throughout 
  the 
  period 
  of 
  work, 
  

   swarms 
  of 
  adults, 
  mainly 
  of 
  three 
  species, 
  settled 
  on 
  the 
  hatchery 
  win- 
  

   dows, 
  having 
  doubtless 
  transformed 
  in 
  the 
  fish 
  troughs. 
  While 
  the 
  ma- 
  

   terial 
  was 
  therefore 
  abundant, 
  only 
  four 
  species 
  were 
  successfully 
  reared. 
  

   Of 
  many 
  species 
  the 
  time 
  of 
  transformation 
  did 
  not 
  fall 
  within 
  the 
  period 
  

   of 
  the 
  work, 
  and 
  consequently 
  a 
  full 
  life 
  history 
  could 
  not 
  be 
  recorded. 
  

  

  The 
  larvae 
  of 
  these 
  insects, 
  as 
  is 
  well 
  known, 
  build 
  for 
  themselves 
  

   cases 
  differing 
  greatly 
  in 
  manner 
  and 
  material 
  of 
  construction. 
  Several 
  

   species 
  of 
  larvae 
  were 
  reared 
  from 
  the 
  egg, 
  and 
  the 
  larvae 
  were 
  observed 
  

   to 
  begin 
  making 
  their 
  cases 
  almost 
  immediately 
  after 
  hatching. 
  Before 
  

   building 
  their 
  cases 
  the 
  young 
  larvae 
  are 
  doubtless 
  at 
  the 
  mercy 
  of 
  many 
  

   enemies. 
  Hydras 
  were 
  seen 
  killing 
  many 
  of 
  them 
  in 
  rapid 
  succession 
  

   but 
  were 
  unable 
  to 
  use 
  them 
  as 
  food 
  because 
  of 
  their 
  size. 
  The 
  charac- 
  

   teristic 
  forms 
  of 
  the 
  cases 
  may 
  be 
  recognized 
  almost 
  from 
  the 
  beginning. 
  

   The 
  cases 
  are 
  enlarged 
  as 
  the 
  growth 
  of 
  the 
  insect 
  demands. 
  The 
  food 
  

   of 
  the 
  larvae 
  is 
  doubtless 
  largely 
  vegetable. 
  Several 
  species 
  were 
  ob- 
  

   served 
  feeding 
  on 
  stonewort, 
  N 
  i 
  t 
  e 
  1 
  1 
  a 
  , 
  and 
  river 
  weed, 
  P 
  o 
  t 
  a 
  m 
  o 
  - 
  

   g 
  e 
  t 
  o 
  n 
  , 
  which 
  flourished 
  in 
  the 
  creek. 
  Some 
  species 
  are 
  however 
  

   known 
  to 
  be 
  carnivorous 
  in 
  their 
  habits. 
  

  

  Well 
  protected 
  by 
  its 
  case, 
  the 
  body 
  of 
  the 
  caddis 
  fly 
  larva 
  needs 
  no 
  

   hard 
  covering 
  of 
  chitin. 
  The 
  head 
  and 
  the 
  thorax, 
  with 
  the 
  three 
  pairs 
  of 
  

   legs, 
  protrude 
  from 
  the 
  case 
  when 
  the 
  larva 
  is 
  moving 
  about 
  or 
  feeding, 
  and 
  

   these 
  parts 
  are 
  protected 
  somewhat 
  more 
  than 
  the 
  other 
  parts. 
  The 
  legs 
  

   terminate 
  in 
  one-jointed 
  tarsi, 
  each 
  of 
  which 
  has 
  a 
  single 
  claw. 
  A 
  spur 
  is 
  

   very 
  prominent 
  at 
  the 
  base 
  of 
  each 
  hook. 
  The 
  abdomen 
  has 
  nine 
  well 
  

   defined 
  segments 
  -and 
  an 
  anal 
  appendage 
  terminated 
  by 
  a 
  pair 
  of 
  hooks 
  

   pointing 
  outward. 
  These 
  hooks 
  can 
  be 
  fastened 
  into 
  the 
  sides 
  of 
  the 
  

   case 
  and 
  thus 
  prevent 
  the 
  forcible 
  eviction 
  of 
  the 
  larva. 
  The 
  dorsal 
  

   side 
  of 
  the 
  first 
  segment 
  is 
  marked 
  by 
  a 
  large 
  protractile 
  tubercle. 
  Two 
  

   smaller 
  tubercles 
  are 
  located 
  on 
  the 
  ventral 
  side 
  of 
  the 
  same 
  segment. 
  

   These 
  tubercles 
  are 
  supposed 
  to 
  serve 
  the 
  larva 
  as 
  a 
  means 
  of 
  maintain- 
  

   ing 
  its 
  position 
  in 
  its 
  case. 
  This 
  view 
  is 
  supported 
  by 
  the 
  fact 
  that 
  a 
  

   species 
  of 
  Hydropsychidae 
  reared 
  at 
  Saranac 
  Inn 
  constructed 
  no 
  larval 
  

  

  