﻿520 
  

  

  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  of 
  smaller 
  size 
  and 
  have 
  the 
  dorsal 
  hooks 
  of 
  the 
  abdomen 
  less 
  developed. 
  

   The 
  following 
  keys 
  will 
  serve 
  for 
  the 
  separation 
  of 
  our 
  imagos 
  and 
  also 
  of 
  

   the 
  nymphs 
  as 
  far 
  as 
  I 
  have 
  been 
  able 
  to 
  find 
  any 
  differences 
  between 
  

   them. 
  

  

  coBtlferum 
  

  

  Fig. 
  30 
  Genitalia 
  of 
  the 
  New 
  York 
  species 
  of 
  Sympetrum 
  (excepting 
  S. 
  cor 
  r 
  upturn 
  Hagen); 
  

   first 
  column, 
  external 
  view 
  of 
  the 
  male 
  genital 
  hamule 
  ; 
  second 
  column, 
  lateral 
  view 
  of 
  male 
  ab- 
  

   dominal 
  appendages 
  ; 
  and 
  third 
  column, 
  ventral 
  view 
  of 
  vulvar 
  lamina 
  of 
  the 
  female, 
  for 
  the 
  

   species 
  named 
  in 
  the 
  figure 
  

  

  KEY 
  TO 
  SPECIES 
  OF 
  SYMPETRUM 
  

  

  Imagos 
  

  

  a 
  With 
  a 
  median 
  transverse 
  ridge 
  incircling 
  the 
  fourth 
  abdominal 
  segment 
  (ia 
  

  

  addition 
  to 
  the 
  normal 
  apical 
  ridge) 
  corruptum 
  

  

  aa 
  With 
  no 
  such 
  added 
  ridge 
  on 
  the 
  fourth 
  abdominal 
  segment 
  

  

  & 
  Superior 
  appendages 
  of 
  the 
  male 
  with 
  a 
  prominent 
  median 
  inferior 
  tooth, 
  

   having 
  some 
  denticles 
  before 
  it; 
  vulvar 
  lamina 
  of 
  the 
  female 
  divided 
  by 
  

   a 
  median 
  cleft 
  into 
  two 
  pointed 
  lobes 
  

  

  