No. 39] ODONATA OF CONNECTICUT: LIBELLULIDAE 279 



Adults. — Wings with less than ten antenodals ; stigma with 

 proximal and distal margins parallel, less than three times as broad, 

 supported usually by two cross-veins ; triangle three-sided, extend- 

 ing nearly as far clistad in the hind wing as in the front ; Mo 

 not sinuate ; subtriangle absent ; Cu^ arising from caudal angle 

 of triangle ; hind lobes of prothorax bilobed and with long hairs ; 

 all femora with only a single ventral row of heavy setae, and these 

 sometimes wanting on the proximal portion ; male abdomen with- 

 out hooks on venter of segment i ; transverse carinae only on 

 segments 2 and 3 ; general color black. 



The nymphs inhabit submerged vegetation, and the adults are 

 usually found near the nymphal habitat. They are not as tireless 

 on the wing as many Libellulids and are not known to congregate 

 in droves. They are fond of bright sunlight. Oviposition is 

 accomplished by the usual method of dipping the abdomen in the 

 water while in flight. 



For literature dealing with adults of the genus see — 

 Hagen, H. Transactions of the American Entomological Society, 17: 229- 



245 : 1890, pi. X. 

 Muttkowski, R. A. Bulletin of the Wisconsin Natural History Society 

 (2), 6: III : 1908. 

 For systematic and descriptive treatises on the nymphs of this genus see — 

 Walker, E. M. Canadian Entomologist, 48: 414-422: 1916: pis. xii, xiii; 

 Ibid., 45 : 168 : 1913. 



Key to Species 

 Nymphs'^ 



1. Dorsal hooks present on abdominal segments 2 to 8 ; venter of 



abdomen without longitudinal dark bands 2 



Abdominal segments 7 and 8 without dorsal hooks, venter of abdo- 

 men with 3 conspicuous longitudinal dark bands (rarely incon- 

 spicuous) 5 



2. Eyes very prominent; lateral spines of segment 9 extending back 



nearly or quite as far as tips of inferior appendages (frigida) 



Eyes less prominent ; lateral spines of segment 9 not extending 

 back as far as tips of inferior appendages 3 



3. Dorsal hook of segment 7 as long as mid-dorsal length of the 



segment, that of segment 8 projecting well over the base of 

 segment 9 ; lateral spines of segment 8 more or less divergent, 

 their outer margins not continuing the regular curve of the 

 abdominal margin ; lateral spines of segment 9 extending beyond 



tips of lateral appendages 4 



Dorsal hook of segment 7 shorter than the mid-dorsal length of 

 the segment, that of segment 8 projecting barely over the base 

 of segment 9, lateral spines of segment 8 slightly convergent, 

 their outer margins continuing the general curve of the abdominal 

 margin ; lateral spines of segment 9 not reaching beyond tips 

 of lateral appendages (proxima) 



4. Spinules on inner margin of lateral lobes of labium mostly in 



groups of 3 ; lateral setae 10 ; dorsal hook of segment 8 not 

 declined, directed straight caudad at apex intacta 



^From Walker, Canadian Entomologist, 48: 415-416: 1916. 



