﻿4l8 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  consisting 
  of 
  single, 
  isolated 
  filaments.^ 
  This 
  subfamily 
  includes 
  the 
  two 
  

   tribes, 
  Capnini 
  and 
  Nemourini 
  of 
  Banks. 
  

  

  Order 
  ephemerida 
  

  

  May 
  flies 
  

  

  Family 
  ephemeridae 
  

  

  The 
  May 
  flies 
  are 
  all 
  aquatic. 
  A 
  few 
  of 
  the 
  larger 
  species, 
  which 
  sud- 
  

   denly 
  appear 
  in 
  countless 
  numbers 
  on 
  the 
  shores 
  of 
  our 
  larger 
  bodies 
  of 
  

   water 
  and 
  as 
  suddenly 
  disappear 
  again, 
  are 
  very 
  well 
  known. 
  But 
  most 
  

   May 
  flies, 
  being 
  less 
  concerted 
  in 
  their 
  period 
  of 
  adult 
  life, 
  emerging 
  a 
  

   few 
  at 
  a 
  time, 
  resting 
  under 
  cover 
  and 
  returning 
  to 
  the 
  water 
  in 
  the 
  

   twilight 
  to 
  oviposit, 
  are 
  little 
  observed. 
  

  

  The 
  nymphs 
  live 
  in 
  all 
  sorts 
  of 
  fresh 
  water, 
  and 
  are 
  almost 
  everywhere 
  

   abundant. 
  They 
  are 
  difl"erentiated 
  into 
  highly 
  specialized 
  groups, 
  each 
  

   finely 
  adapted 
  to 
  its 
  own 
  peculiar 
  situation. 
  There 
  is 
  great 
  apparent 
  

   similarity 
  among 
  the 
  images 
  ; 
  but 
  the 
  nymphs 
  of 
  the 
  several 
  principal 
  

   groups 
  are 
  strikingly 
  unlike. 
  The 
  struggle 
  for 
  existence 
  has 
  fallen 
  mainly 
  

   on 
  the 
  nymphs, 
  and 
  they 
  have 
  speciaHzed 
  for 
  themselves, 
  more 
  or 
  less 
  

   independently 
  of 
  adult 
  life. 
  On 
  this 
  account, 
  the 
  beginner 
  will 
  find 
  the 
  

   study 
  of 
  the 
  group 
  greatly 
  facilitated 
  by 
  collecting 
  the 
  nymphs 
  along 
  with 
  

   the 
  adults. 
  

  

  Nathan 
  Banks 
  has 
  twice 
  published 
  keys 
  for 
  the 
  determination 
  of 
  the 
  

   genera 
  of 
  our 
  North 
  American 
  May 
  fly 
  images, 
  in 
  the 
  Transactions 
  of 
  the 
  

   American 
  entomological 
  society^ 
  19:332 
  and 
  26:246-47. 
  Nearly 
  all 
  our 
  

   species 
  are 
  described 
  in 
  Eaton's 
  monograph.^ 
  The 
  following 
  table 
  will 
  

   serve 
  for 
  the 
  separation 
  of 
  the 
  nymphs 
  of 
  the 
  genera 
  occurring 
  in 
  our 
  

   fauna. 
  It 
  will 
  also 
  serve 
  to 
  indicate 
  what 
  I 
  believe 
  to 
  be 
  the 
  three 
  

   principal 
  natural 
  divisions 
  of 
  the 
  family, 
  corroborated 
  by 
  important 
  

   characters 
  pertaining 
  to 
  both 
  adult 
  and 
  nymphal 
  life. 
  It 
  is 
  based 
  in 
  

   part 
  on 
  the 
  figures 
  and 
  tables 
  of 
  Pictet^ 
  , 
  Vaysseire"^ 
  , 
  Eaton^ 
  , 
  and 
  

   Schiller 
  ^, 
  but 
  mainly 
  on 
  my 
  own 
  breedings 
  of 
  New 
  York 
  May 
  flies. 
  So 
  

   few 
  species 
  have 
  as 
  yet 
  been 
  reared 
  that 
  this 
  table 
  will 
  doubtless 
  need 
  

   considerable 
  revision 
  when 
  more 
  of 
  the 
  nymphs 
  are 
  known. 
  

  

  1 
  Rarely 
  developed. 
  They 
  are 
  known 
  from 
  the 
  European 
  Nemoura 
  cinerea 
  Oliv., 
  in 
  which 
  

   species 
  there 
  are 
  six 
  separate 
  filaments 
  at 
  the 
  front 
  end 
  of 
  the 
  prothorax 
  beneath. 
  An 
  undetermined 
  

   species 
  of 
  Nemoura, 
  bred 
  by 
  me 
  at 
  Ithaca 
  N. 
  Y, 
  possessed 
  no 
  gills 
  whatever. 
  I 
  also 
  bred 
  at 
  

   Ithaca 
  an 
  undetermined 
  species 
  of 
  Taeniopteryx 
  the 
  nymph 
  of 
  which 
  had 
  attached 
  to 
  the 
  

   posterior 
  side 
  of 
  each 
  coxa 
  a 
  single, 
  tapering, 
  three 
  jointed, 
  telescopic, 
  gill 
  filament. 
  

  

  In 
  the 
  Perlinae, 
  the 
  number 
  of 
  filaments 
  in 
  a 
  tuft 
  often 
  increases 
  with 
  the 
  age 
  and 
  size 
  of 
  the 
  

   nymph. 
  

  

  2 
  Eaton. 
  Revision 
  al 
  monograph 
  o 
  recent 
  Ephemerlnae. 
  Linn. 
  soc. 
  Lond. 
  Trans. 
  (2) 
  3, 
  1888. 
  

  

  3 
  Pictet. 
  Histoire 
  naturelle 
  des 
  neuropteres 
  : 
  Ephemer. 
  Paris 
  184a. 
  

  

  4 
  Vaysseire. 
  Organization 
  des 
  larves 
  des 
  Ephemerines. 
  Sci. 
  nat. 
  zool. 
  Ann. 
  (6) 
  11, 
  1881. 
  

  

  5 
  Schiller. 
  Die 
  Ephemeriden-larven 
  Sachsens. 
  Sitz. 
  u. 
  abh. 
  der. 
  naturwiss. 
  ges. 
  Isis 
  in 
  Dresden^ 
  

   1890. 
  p. 
  44-49, 
  2 
  pi. 
  

  

  