Sept.-Dec, I9i8.] DaVIS : MISSISSIPPI CiCADAS. 143 



of mcsonotum. Opcrcula rather large, nearly touching on inner 



margin Tibicina Kolenati. 



Head, including eyes, much narrower than base of mesonotum. Oper- 



cula small with extremities far apart Okanagana Distant. 



Cells of median area of fore wings of about the same length or shorter 

 than the marginal cells. 

 Very small species Melampsalta Kolenati. 



Key to Species of the Genus Tibicen founb in the Southeastern 

 United States. 



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 

 markings and black area on the central part of the abdomen 

 beneath, except in sayi, and new variety of davisi. 

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



A narrow irregular area of black on the under side of the ab- 

 domen ; opercula short and broad, and usually in the males 

 an attenuated, pruinose stripe each side on the dorsum of 



segment three pruinosa (Say). 



Dorsum of abdomen with the hind margin of the segments 

 more or less brown and generally but a trace of pruinose 

 stripe each side on segment three. 



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. 

 pruinosa var. latifasciata (Davis.) 

 A longitudinal band of black on the under side of the ab- 

 domen, the opercula more lobate, and the margin of the 

 front wings suddenly bent near the middle. 



linnei (Smith & Grossbeck). 



A definite longitudinal band of black on the under side of 



' the abdomen ; head with the front rather prominent. Not 



a large species canicularis (Harris). 



An irregular band of black on the under side of the abdomen, 

 head rounded in front ; a rather small species. 



davisi (Smith & Grossbeck). 

 Abdomen greenish centrally on under side, blackened area 

 wanting, marginal cells of fore wings clouded. 



davisi var. harnedi new variety. 

 CC. Hind margin of pronotum or collar black or nearly so (except in 

 sayi \ar. austral is). 

 D. Central area of the abdomen beneath black. 



