442 PROCEEDINGS OF THE AMERICAN ACADEMY. 



Stal first brought together the synonymy of the species known to him, in 

 his Recensio Orthopterorum ; and a number of described forms are still 

 indeterminable with the considerable material I have brought together 

 for their study. Especially is this true of Walker's species, his genera 

 Acridium and Cyrtacanthacris being heterogeneous assemblages of species 

 of many genera, and usually quite impossible of determination apart from 

 the specimens themselves in the British Museum. 



Unfortunately, a not inconsiderable part of the material on which the 

 species are here separated is not so good as one could wish, being speci- 

 mens dried after previous immersion in spirits, — a favorite mode of 

 collecting these bulky Acridians, but one which dulls the coloring and 

 often exaggerates the salient parts of the structure of the head and pro- 

 notum. I have therefore relied as little as possible on mere color, which 

 nevertheless plays a very important part in the distinction of species in 

 this genus. It takes a longer immersion to destroy the markings, but 

 these also are sometimes lost. On this account I have been obliged to 

 discard a small part of my material, which seemed to indicate additional 

 species coming from localities, from which one rarely obtains specimens. 



Of the forty-four species here tabulated, eleven are known from the 

 United States, twenty-three from Mexico or Central America, six from 

 the West Indies, and twenty from South America (including the Gala- 

 pagos), besides one of which the provenance is unknown, but which 

 probably belongs to South America. 



I am indebted to my friends, Messrs. S. Henshaw, A. P. Morse, and 

 L. Bruner, for loans from their collections, and have had all the material 

 from Central and South America in the Museum of Comi)arative Zoology 

 for study. The main portion of my material is found in my own collec- 

 tion. Only the new forms are described, but the following table will 

 enable one to determine any of the species I have seen, new or old. 



Table of the Species of Schistocerca. 



ai. Antennae of male (those of female always relatively sliorter) nearly or quite 

 one third, often one half, longer than liead and pronotum together. 



M. Pronotum rectangulate behind, or in tlie female faintly obtusangulate, the 

 angle narrowly or very narrowly rounded. 



ci. Tegmina distinctly maculate or if occasionally feebly and obscurely macu- 

 late, then the pronotum is unstriped above ; lateral lobes rarely with any 

 markings, and when present rarely separated obliquely. 



d^. Pronotum with no, or at most very obscure, dorsal stripe, the lateral 

 lobes at most clouded with fuscous. 



