SUBFAMILY i. TETRIGINM:. 155 



Subfamily I. TETRIGINJE. 



In addition to the characters given in key the members of this 

 subfamily differ from those of I'atrachidimp in haying the body 

 much more slender; ridges of frontal costa more or less divergent 

 or forked above the ocellus; antenna^ inserted opposite the lower 

 border of eves; proiiotum more tapering, less icctiforni, more 

 often granulate, but usually less rugose, its median carina usu- 

 ally higher, often cristate; hind tarsi with first segment distinctly 

 longer than third. Five genera are recognized as being repre- 

 sented in our territory. 



KEY TO EASTERN GENERA OP TETRIGINJE. 



a. Vertex more or less produced forward beyond the front of eyes, 

 viewed from above distinctly wider than one of them, its front mar- 

 gin angulate or rounded, not truncate (Figs. 2b, 3); dorsal surfac-- 

 of pronotum usually tectiform or sloping between the shoulders. 

 b. Ridges of frontal costa but feebly forked; front dorsal margin of 

 pronotum when truncate not advanced upon the head to the 

 eyes (Figs. 2b, 3); front of vertex, viewed from the side, angu- 

 late or subrounded. 



c. Pronotum with its median carina raised in the form of a crest 

 and more or less arched lengthwise, its dorsal front margin 

 produced in an angle over the back of head (Figs. 1, Id); teg- 

 minal or upper notch of lateral lobe of pronotum only about 

 one-half as deep as the lower one; posterior process of prono- 

 tum usually much abbreviated (Fig. 1.) I. NOMOTETTIX. p, 156. 

 cc. Fronotum with median carina low, not arched, its dorsal front 

 margin truncate or very obtuse-angulate (Figs. 2b, 3); hind 

 margin of lateral lobes strongly bisinuate, the tegminal sinus 

 usually nearly as deep as the lower one (Fig. 2a.) 



II. ACRYDIUM, p. 161. 



bb. Ridges of frontal costa with their lower halves widely divergent 

 or forked; front dorsal margin of pronotum advanced upon the 

 head to the eyes; vertex usually much wider than one of the 

 eyes, its front, when viewed from the side, distinctly rounded. 



III. NEOTETTIX", p. 171. 



. Vertex not at all or barely advanced beyond the eyes and usually nar- 

 rower than one of them, its front margin truncate or nearly so; 

 dorsal surface of pronotum convex between the shoulders, its front 

 margin reaching the eyes, (Fig. 4.) 



d. Frontal costa, in profile, feebly but distinctly sinuate in front of 

 eyes (Fig. 4a) ; vertex truncate, narrower than or subequal in 

 width to one of the eyes (Fig. 4), its frontal carinulae interrupted 



"After examing the type of Neotettix proavus R. & H. at Philadelphia and taking in- 

 to consideration the fact that the long-winged form mentioned bv Fox (1018) had the 

 hind margin of pronotum bisinuate, I follow Hebard (1919) in making the" genus Caro- 

 tettiv Hancock (1918), a synonym of Neotettir 



