246 



FAMILY VI. ACRIDIDJE. THE LOCUSTS. 



a. 



aa. 



KEY TO TRIBES OF EASTERN GENERA OF CEDIPODIN^. 



Median carina of pronotum either entire or cut by only one trans- 

 verse sulcus." (Fig. 90, a, c.) Tribe I. HIPPISCI, p. 246. 



Median carina of pronotum cut by two sulci, the front notch often 

 much less distinct than the hind one (Fig. 10G, c.) 



Tribe II. TRIMEROTROPI. p. 286. 



Fig. 90. Side and dorsal views of the pronotum of Arphia and Sphar- 



at/cinon. a, of Arpliia sulphured; b, of A. .vanthoptcra; c and d, of Sphar- 



agcmon bolli; e and /, of 5". ivyomingiannm; g and h, of .. saxaiile. (After 

 Morse and Walden.) 



Tribe I. HIPPISCI. 



This tribe comprises our largest, most widely distributed and 

 best known Oedipods, and some of them are among the largest of 

 our eastern locusts. Our eight genera representing the tribe may 

 be separated by the following table in which I have made use of 

 many characters not of generic importance, in order that the be- 

 ginner may the more readily determine the specimens in hand. 



KEY TO EASTERN GENERA OF TRIBE HIPPISCI. '- 



o. Median carina of pronotum raised in a distinct crest which is usually 

 entire, rarely very feebly cut by the principal sulcus (Fig. 90, a. 

 b) ; tegmina subcoriaceous or leathery in texture, densely and ir- 

 regularly reticulate; inner wings brightly colored, red or yellow at 

 base. I. ARPHIA, p. 248. 



aa. Median carina of pronotum less prominent, always distinctly cut by 

 one sulcus (Fig. 90, c, e) ; tegmina with apical half membranous 

 and regularly reticulate, 

 b. Basal portion of inner wings pellucid or transparent, sometimes 



41 Very rarely a specimen of Scirtetica, one of the genera of Hippisci, has the median 

 carina of prozona feebly cut by the front transverse sulcus, thus causing an evident second 

 notch. More rarely the front notch in Psinidia, a genus of Trimcrotropi, is subobsolete 

 or very faint. 



42 I have not followed R. & H. in separating Pardalophora Saussure from Hippiscus as 

 the principal distinguishing character he gives (1884, 83) for the latter, viz., the dividing 

 of the disk of the vertex by transverse and longitudinal carinse into four areolae, is an in- 

 dividual and not even a specific, let alone a generic character. In at least half of_the 

 specimens of both H. phaemcppterus and H. haldcmanni at hand these carinae are as plainly 

 visible as in H. nigosus, while in the others they are wholly wanting. 



