38 Journal New York Entomological Society. [Voi. xxx. 



Key to the Genera of Virginia Cicadas. 

 {Okanagana is included as it may occur in the mountains.) 



Tympanal coverings concealing tympanal orifices. 



Head large and broad; body walls of abdomen thickened; opercula 



large Tibicen Latreille. 



Head small ; abdomen translucent ; opercula very small. 



Cicada Linnaeus. 

 Tympanal coverings absent. 



Cells of median area of fore wings (ulnar cells) longer than marginal 

 cells; median and cubitus veins of fore wings not united but 

 reaching basal cell or arculus separately. 

 Uncus retractile within abdomen of male ; opercula rather large, 



nearly touching on inner margin Tibicina Kolenati. 



Uncus not retractile within abdomen of male but exposed; opercula 



small with extremities far apart Okanagana Distant. 



Cells of median area of fore wings (ulnar cells) of about the same length 

 or shorter than marginal cells ; median and cubitus veins united 

 near base of fore wing and reaching the basal cell or arculus as a 

 single vein. Very small species Melampsalta Kolenati. 



Key to the Species of the Genus Tibicen found in Virginia. 



A. Large, heavy -bodied species ; head broad, uncus simple, and first cross 

 vein in the fore wings starting from radius 3 far back, or about one 

 third distant from base of first marginal cell. 

 B. Uncus longer than broad. Black species with green or greenish mark- 

 ings and black area on the central part of the abdomen beneath, 

 except in sayi. 

 C. Hind margin of pronotum or collar green or greenish. 



Dorsum of abdomen with the hind margin of the segments more 

 or less brown and generally but a trace of a pruinose stripe 

 each side on segment three ; a narrow irregular area of 

 black on the under side of abdomen ; opercula short and 

 broad, obliquely truncated on the inner side. Expands about 



95 mm pruinosa var. winnemanna (Davis). 



Dorsum of abdomen shining black with a broad pruinose mark 

 each side on segment three; blackened area on under side 

 of abdomen more in the nature of an even stripe. Found 

 near the coast. Expands about 95 mm. 



pruinosa var. latifasciata (Davis). 



Dorsum of abdomen shining black without any white stripe each 



side on segment three ; blackened area on under side of 



abdomen a distinct shining stripe ; extremities of opercula 



