V4 Key to Families of North American Insects. 



3. Ocelli (rarely absent) placed between the eyes (PI. 16, fig. 377), on the vertex, on 



the front, or on the front margin of the head 4 



Ocelli placed beneath or near the eyes, usually in cavities of the cheeks ; pronotum 

 neither armed nor unusually developed. (FuLGORoiDEA) 8 



4. Pronotum prolonged backwards into a hood or process of variable form extend- 



ing over the abdomen and usually much elevated; antennae inserted between 

 and in front of the eyes. Tree-hoppers. (Ceresa [C. bubalus, Buffalo 

 tree-hopper], Enchendpa, Telamdna) (PL 14, fig. 345; PL 15, fig. 350, 



351, 352; PL 16, figs. 370, 372) MEMBRACDXE 



Pronotum not prolonged over the base of the abdomen 5 



5. Tibiae smooth, the hind pair armed with one or two stout spines and with a 



cluster of spinules at apex; ocelli placed on the vertex, rarely absent. 



Spittle insects. (Aphrophora, Clastdptera.) CERCOPIDjE 



Hind tibire with a double series of spines beneath; ocelli variable in position, 

 rarely absent. Leaf-hoppers 6 



6. Veins of the fore wings branching on the disk so that they form a series of pre- 



apical cells 7 



Veins of the fore wings branching at the apex and passing without fork to the 

 apical cells; ocelli usually absent. (Typhlocyba [T. comes, Grape leaf-hop- 

 per], Empoasca [E. mali, Apple leaf-hopper]) (PL 15, fig. 353). 



TYPHLOCYBIDJE 



7. Head very short, vertex sloping or rounding on to the front; ocelli on the front. 



(Bythoscopus, Idiocerus.) BYTHOSCOPIIXE 



Head more or less prominent; ocelli placed on the disk of the vertex. (Diedro- 

 cephala, Tettigoniella (= Tettigonia], Gypona) (PL 15, figs. 354, 357). 



(TETTIGONIIDfil} PROCONHDJE 



Head produced or rounded; ocelli on the margin between the vertex and front. 

 (Acocephalus, Deltocephalus, Thamnotettix) (PL 15, fig. 355) . . JASSID^E 

 S. Anal angle of wings net-veined; the ridge separating the front from the cheeks 

 contiguous on the sides of the clypeus. (Poiocera) (PL 15, fig. 356). 



FULGORIDJE 

 Anal area of wings rarely net-veined, when so, the clypeus without lateral 



ridges 9 



9. Hind tibiae without a mobile spur at apex 10 



Hind tibiae with a long, robust, mobile spur at apex. (Liburnia Stobaera) 



(PL 15, fig. 359) '. DELPHACmE 



10. Clavus very rarely granulate, pointed at apex, rarely somewhat obtusely, 

 but distinctly closed; two veins remote or very remote from the apex, some- 

 times united in one beyond the middle of the clavus; costa very rarely 

 dilated; tegmina sometimea shortened or fused with clavus or corium. . . .11 

 Clavus granulate, apex sometimes subacute and closed, sometimes very obtuse 

 and broadly open, with two veins separated through the entire length or 

 united in one near apex; costa dilated; costal membrane transversely veined; 

 claval suture distinct. (Ormenis, Amphiscepha, ChlorochrSa) (PL 15, 

 figs. 358, 361) FLATID^S 



