464 NEW YORK STATE MUSEUM 



Nymphs 



These are known for all the foregoing genera except G o m p h - 

 aeschna: the nymphs figured and described by Cabot and referred 

 by supposition to that genus, were the males of B o y e r i a (see below 

 under the account of that genus). Among all our nymphs that are still 

 unknown, that of Gomph aeschna remains one of the most de- 

 sirable discoveries yet to be made. 



a Hind angles of the head viewed from above, sharply angulate 



& Lateral lobe of labium squarely truncate on apex Boyeria 



Vb Lat eral lobe of labium with taper-pointed apex Basiaeschna 



aa Hind angles of the head obtusely rounded 



& With lateral spines on abdominal segments 4-, 5- or 6-9. 

 c With lateral spines on segments 4-, or 5-9 



d With dorsal hooks on abdominal segments 7-9 Nasiaeschna 



dd With no dorsal hooks on abdomen Epiaesohna 



cc With lateral spines on abdominal segments 6-9 Aeschna 



Z>6 With lateral spines on abdominal segments 7-9... Anax 



So well marked are these genera that their nymphs may be recognized 

 by the following 



Single distinctive characters 



Nasiaeschna alone has dorsal hooks on the abdomen. 

 Basiaeschna alone has the apices of its lateral labial lobes pointed. 

 Anax alone has lateral spines on abdominal segments 7-9 only. 

 Aeschna alone has lateral spines on abdominal segments 6-9 only. 

 Boyeria alone has two teeth on the front border of the median lobe 



of the labium, at a distance either side from the median cleft. 

 Epiaeschna alone is lacking in all the above characters. 



GOMPHAESCHNA 



The single regional species G. furcillata Say has not been taken 

 as yet within this state, so far as records show. Its nymph is unknown, 

 that one referred to this species by Cabot on supposition proving to be 

 the male nymph of Boyeria, described below. 



BOYERIA 



This genus includes the single North American species. 

 Boyeria vinosa Say 



1839 Aeschna vinosa Say, Acad. nat. sci. Phil. Jour. 8 : 13 

 1839 Aeschna 4-guttata Burmeister, Handb. ent. 2 : 837 

 1861 Aeschna 4-guttata Hagen, Synopsis Neur. N. Am. p. 130 

 1875 Neuraeschna vinosa Hagen, Bost. soc. nat. hist. Proc. 18:37 (full 

 bibliography and distribution) 



