THE ORTIIOPTERAN GENUS SCIIISTOCERCA. 



By Samuel H. Scudder. 



Received February 20, 1899. Presented March 8, 1899. 



ScHiSTOCERCA belongs to the Acridii, the typical group of AcridiinaB, 

 in which the fastigium is dellexed and passes insensibly into the frontal 

 costa, lateral carintE are wanting on the pronotum, the mesosternal lobes 

 are longer than broad and usually produced and strongly acutangulate 

 posteriorly on the inner side, the hind tibi;e have smooth margins with 

 numerous spines regularly disposed on both sides, but with no apical spine 

 on the outer margin, and the second tarsal joint is only half as long as 

 the first. 



There is but one other genus in the group, Acridium, from which 

 Schistocerca was separated by Stal in 1873, on account of the apically 

 broader anal cerci of the male and the apically fissate subgenital plate of 

 the same sex. In doing this he also separated the Old World species of 

 Acridii from those of the New "World, for Acridium does not occur in 

 America and Schistocerca is found only in the New World, except for a 

 single species, which occurs both in South America and in Africa, but 

 which has also been found in such circumstances in mid-ocean as to render 

 it in the highest degree probable that Africa was originally colonized from 

 America. 



Schistocerca is therefore normally an American genus. Like Acridium 

 it is composed of large species with a wing expanse usually reaching 

 nearly or quite a decimeter, though it contains more species of a moderate 

 size than does Acridium, and some much smaller than any Acridium 

 known to me. Two at least of the larger forms, including the species 

 common to the two worlds, are known to be both migratory and very 

 destructive ; but the greater number appear to do less harm than their 

 large size would lead us to expect. The species of Acridium are mostly 

 confined to Africa, southern Asia, and Australia, and many species are 

 apparently still undescribed. 



A considerable number of species of Schistocerca have been described 

 from America, but many have received more than one name, even since 



