hh. Head larger, distim-tlyexserted, the hiud part as wide 



or very little narrower than front edge of pronotiiui. 



i. Pronotuni dilated behind. Cerei of male wiili the 



apex graceful. DICHHOl'IA'S Stal. 



ii. Prouiitinn cvliudrical. Cerei of male broadlj' .spat- 



ulate. " SCOTTUSSA Giglio-Tos. 



gg. Tegmina lol)iform, lateral, di.stant from one anothei', or 



meeting above, but never with the edges overlapping. 



h. Prouotum with the po.sterior edge rounded. Head very 



large, distinctly wider than the ])Osterior portion of 



pronotum. Cerei of male, excej)! of base. stvlifoi-m. 



SCOPAS (iiglio-To.s. 



hh. Pronotum with the posterior edge truncate or emar- 



giuate. Head much smaller, not as wide as hind 



border of pro otum. Cerei of male more or less 



flattened and curved. 



PAKADICHHOPLIS Brunner. 

 ff. Posterior tibiie generally with less than eight spines, usti- 

 sually with six to seven, in outer row. Frontal eosla 

 percurrent. straight, not at all or but little produced be- 

 tween the antenna'. Tegmina and winsjs fullv devel- 

 oped. O'SMlLIAStal. 



GENUS PRIONOLOPHA, STAL. 

 P. serrntd (Linii.) This large locust has been taken in 

 the i^rovinces of Tncuman, Salta, Jujuy and the territory of 

 the Chaco (Gigiio-Tos). 



GENUS TROPIDONOTUS, SERV. 

 TABLE FOR SEPARATING THE SPECIES. 

 A. Crest of the pronotum more or less erenulate or even serrulate i)os- 

 teriorly. Genicular angles of hind femora acixte. a little lengthened, 

 b. Tegmina testaceotis. more or less mottled with brown, 

 e. The markings of tegmina large, forming more or less well-delined 

 l)ands. 

 d. Hind femora very long, reaching considerably beyond the tip 

 of abdomen in" botli sexes. Crest of pronotum deeply cleft 

 bv all three sulci, the lobes distinctly separated. 



diiscoideiis Serv. 

 dd. Hind femora shorter, only reaching the tip of abdomen (fe- 

 male) or but little surpassing it (male). Crest of pronotum 

 less deeply cleft, the lobes closely approximate, 

 e. General color grayish-brown. Tegmina with the markings 

 distinct or apical as well as on basal half. Aiit<Min;r dusky. 



aiijiulatus Stal. 

 ee. General color ferruginous ttstaceous. Tegmina with a large 

 triangular spot on l)asal half, the apical portion almost 

 without trace of markings. Antenna* dusky only at tip. 



Sclmlzi Brniier. 

 ce. Markings of tegmina small, irregularly scattered over the wing 

 save for a row in basal half of tliscal area, 

 il. Pronotum sliort. the crest low. and but little proiluced posteri- 

 orly. Hind tibi;e with nine spines in outer row. 



iiioclestii.'^ (Jiglio-Tos. 



