﻿Order 
  PLECOPTERA. 
  

  

  The 
  "Stone 
  flies" 
  which 
  constitute 
  this 
  order 
  are 
  loose-jointed, 
  flat- 
  

   tened, 
  soft-bodied 
  creatures 
  with 
  long 
  net-veined 
  wings, 
  the 
  hind 
  pair 
  

   longitudinally 
  folded 
  beneath 
  the 
  anterior. 
  The 
  head 
  is 
  large, 
  the 
  

   mouth 
  parts 
  are 
  soft, 
  antennae 
  long 
  and 
  tapering, 
  eyes 
  rather 
  prominent. 
  

   The 
  prothorax 
  is 
  free 
  and 
  quadrate, 
  the 
  other 
  segments 
  loosely 
  jointed. 
  

   The 
  abdomen 
  is 
  soft 
  and 
  usually 
  with 
  anal 
  filaments 
  or 
  processes. 
  These 
  

   "flies" 
  are 
  found 
  along 
  the 
  streams 
  and 
  rivers 
  in 
  which 
  their 
  larvae 
  occur, 
  

   resting 
  on 
  the 
  leaves 
  and 
  not 
  easily 
  disturbed; 
  their 
  flight 
  is 
  heavy 
  and 
  

   they 
  do 
  no 
  feeding 
  upon 
  living 
  plants 
  so 
  far 
  as 
  known. 
  The 
  larvae 
  live 
  

   in 
  streams 
  under 
  stones 
  to 
  which 
  they 
  cling 
  so 
  closely 
  that, 
  being 
  very 
  

   much 
  flattened 
  they 
  are 
  easily 
  overlooked. 
  They 
  breathe 
  by 
  means 
  of 
  

   lateral 
  gill 
  tufts 
  which 
  occur 
  also 
  on 
  the 
  head, 
  and 
  which, 
  in 
  some 
  species, 
  

   persist 
  even 
  in 
  the 
  adult 
  stage; 
  a 
  curious 
  reminder 
  of 
  ancient 
  conditions 
  

   and 
  an 
  indication 
  of 
  the 
  primitive 
  character 
  of 
  this 
  order! 
  The 
  pup^ 
  are 
  

   active 
  and 
  the 
  transformation 
  is 
  incomplete. 
  They 
  form 
  an 
  important 
  

   feature 
  of 
  the 
  aquatic 
  fauna 
  in 
  numbers 
  of 
  individuals 
  as 
  well 
  as 
  of 
  

   species, 
  but 
  are 
  of 
  no 
  economic 
  importance. 
  

  

  Since 
  the 
  previous 
  edition 
  quite 
  a 
  number 
  of 
  genera 
  and 
  species 
  have 
  

   been 
  taken, 
  practically 
  all 
  of 
  which 
  have 
  been 
  determined 
  by 
  Mr. 
  Banks. 
  

  

  Fig. 
  5. 
  — 
  A 
  stone-fly 
  and 
  its 
  larva. 
  

  

  Family 
  PERLID^. 
  

  

  PTERONARCYS 
  Newn. 
  

  

  P. 
  nobilis 
  Hagen. 
  New 
  York 
  to 
  Tennessee. 
  

   P. 
  regal 
  is 
  Newn. 
  Philadelphia, 
  and 
  certainly 
  

   occurs 
  in 
  New 
  Jersey. 
  

  

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