AQUATIC INSECTS IN THE ADIRONDACKS 493 



SPECIES OF TETRAGONEURIA 



Imagos 



a Frons with a black T-spot above; triangle of hind wings generally without 



a cross vein spinigera 



aa Frons without a T-spot above ; triangle of hind wings generally traversed by 



a cross vein 



& Superior appendage of the male not declined at tip, and without superior 



ante-apical spine. Hind wings generally with four antenodal cross veins. 



c Hind wing with isolated basal streaks which hardly surpass the level of 



the first antenodal cross vein cynosura 



CG Hind wings with broader, and more confluent markings, reaching the 



level of the third or fourth autenodal cross vein semiaquea 



hi The superior appendage of the male strongly declined at the lip beyond a 

 superior ante-apical spine ; hind wings generally with five antenodal cross 

 veins, some of the antenodals surrounded by fuscous spots. .. s p i n o s a 



a Spines of the ninth abdominal segment strongly divergent, their tips dis- 

 tinctly wider apart than their bases on the outer sides s p in ig era 



aa Lateral spines of the ninth segment, very slightly or not at all divergent 

 & Spines of the ninth abdominal segment longer than the segment 

 c Spines of the ninth segment hardly longer than is the segment on its 



dorsal side (fig. 20) cynosura 



cc Spines of the ninth segment one third to one half longer than is the 



segment on its ventral side semiaquea 



hi Spines of the ninth segment distinctly shorter than that segment, and 

 slightly incurved at tips spinosa, supposition 



Tetragoneuria spinigera Selys 



1871 Tetragoneuria spinigera Selys, Acad. Belg. (2) Bui. 31:269 

 1897 Tetragoneuria spinigera Van Duzee, N. Y. ent. soc. Jour. 5:90 



(listed from Buffalo) 

 1897 Te tragon euria spinigera Calvert, N. Y. ent. soc. Jour. 5:95 



(listed from Buffalo) 

 1900 Te tr agone u ria spinigera Williamson, Dragon flies Ind. p. 311 



(description) 

 To the above record by Van Duzee of this species from Buffalo 

 (repeated by Calvert in his Hst), I have to add two localities. It was 

 exceedingly abundant at Saranac Inn during the month of June, flying 

 about the grounds of the hatchery in company with the other two species 

 occurring there — flying, also, about every other little clearing in the 

 forest, foraging. It was very common toward the mouth of Buttermilk 

 creek near Ithaca in June 1897. 



