﻿72 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  marked 
  dilatation 
  of 
  the 
  lateral 
  margins 
  of 
  the 
  abdomen 
  than 
  even 
  

   Oniscigaster 
  wakefieldi. 
  Its 
  abdomen 
  is 
  more 
  than 
  

   onisciform: 
  it 
  is 
  as 
  veritable 
  parachute. 
  The 
  expansion 
  involves 
  seg- 
  

   ments 
  5 
  to 
  9 
  of 
  the 
  abdomen 
  (inO. 
  wakefieldi, 
  only 
  6 
  to 
  9) 
  , 
  

   and 
  begins 
  and 
  ends 
  more 
  abruptly 
  than 
  in 
  the 
  New 
  Zealand 
  

   species. 
  Our 
  insect 
  distinguishes 
  itself 
  from 
  Oniscigaster, 
  how- 
  

   ever, 
  by 
  lacking 
  a 
  median 
  caudal 
  seta, 
  and 
  by 
  a 
  symmetrical 
  fork- 
  

   ing 
  of 
  the 
  median 
  vein, 
  that 
  forking 
  'being 
  very 
  unsymmetrical 
  in 
  

   Oniscigaster. 
  And 
  since 
  in 
  these 
  respects 
  it 
  agrees 
  with 
  the 
  genus 
  

   Siphlurus, 
  which 
  stands 
  in 
  the 
  system 
  next 
  Oniscigaster, 
  I 
  was 
  at 
  

   first 
  inchned, 
  in 
  spite 
  of 
  the 
  parachute, 
  which 
  in 
  Oniscigaster 
  is 
  

   certainly 
  of 
  no 
  great 
  systematic 
  consequence, 
  to 
  refer 
  it 
  to 
  Siph- 
  

   lurus. 
  By 
  my 
  key 
  in 
  Bulletin 
  86, 
  N. 
  Y. 
  State 
  Museum, 
  page 
  22, 
  

   it 
  would 
  be 
  traced 
  to 
  Siphlurus, 
  with 
  the 
  discrepancy 
  that 
  there 
  is 
  

   no 
  backward 
  prolongation 
  of 
  the 
  sternite 
  of 
  the 
  9th 
  abdominal 
  seg- 
  

   ment 
  in 
  the 
  female. 
  It 
  differs 
  from 
  Siphlurus, 
  also, 
  in 
  having 
  the 
  

   claws 
  of 
  the 
  forefeet 
  differentiated 
  from 
  those 
  of 
  the 
  other 
  feet, 
  

   being 
  obtuse 
  and 
  inflated 
  and 
  not 
  at 
  all 
  clawlike 
  in 
  form: 
  also, 
  in 
  

   having 
  the 
  radial 
  sector 
  in 
  the 
  hind 
  wing 
  twice 
  dichotomously 
  

   and 
  symmetrically 
  forked. 
  I 
  think 
  therefore 
  that 
  this 
  species 
  repre- 
  

   sents 
  a 
  genus 
  distinct 
  from 
  both 
  Siphlurus 
  and 
  Oniscigaster, 
  

   although 
  closely 
  allied 
  to 
  both, 
  and 
  as 
  such 
  I 
  describe 
  it 
  below. 
  

   Probably 
  the 
  male, 
  and 
  the 
  nymph 
  if 
  known, 
  would 
  add 
  other 
  

   differential 
  characters. 
  

  

  Siphlonisca 
  gen. 
  nov. 
  

  

  Caudal 
  setae 
  two, 
  slightly 
  longer 
  than 
  the 
  body. 
  Claws 
  of 
  the 
  

   front 
  tarsus 
  inflated 
  and 
  obtuse 
  ; 
  those 
  on 
  the 
  other 
  tarsi 
  hooked 
  

   and 
  clawlike, 
  and 
  similar 
  each 
  to 
  each. 
  Hind 
  tibia 
  longer 
  than 
  its 
  

   tarsus 
  : 
  last 
  segment 
  of 
  tarsus 
  longest, 
  in 
  all 
  the 
  feet. 
  Median 
  and 
  

   cubital 
  veins 
  in 
  the 
  forewing 
  symmetrically 
  forked, 
  and 
  the 
  radial 
  

   sector 
  in 
  the 
  hind 
  wing 
  equally 
  twice 
  forked 
  : 
  no 
  humeral 
  angula- 
  

   tion 
  of 
  hind 
  wing. 
  Mesothorax 
  with 
  a 
  prominent 
  midventral 
  

   spine. 
  Abdomen 
  with 
  conspicuous 
  lateral 
  expansion 
  of 
  the 
  middle 
  

   segments. 
  

  

  Type 
  the 
  following 
  species. 
  

  

  Siphlonisca 
  aerodroniia 
  sp. 
  nov. 
  

   Length 
  (J) 
  19 
  mm, 
  setae 
  20 
  mm 
  additional; 
  expanse 
  of 
  wings 
  

   37 
  mm. 
  Abdomen 
  13 
  mm 
  long 
  and 
  2 
  mm 
  wide, 
  expanded 
  to 
  4 
  mm 
  

   wide 
  on 
  the 
  5th 
  to 
  9th 
  segments. 
  

  

  