DERMAPTERA AND ORTHOPTERA 265 



of them reach into Mexico, with, however, the greater part of the 

 known range of three north of the Mexican boundary. One, 6*. 

 mexicana, is but narrowly intrusive in our territory from Mexico. 

 Also in the eastern, central, and southeastern United States are 

 four other lines of the genus, two there limited, one largely re- 

 stricted to that area, and the fourth also found rather broadly and 

 passing into Mexico, but almost limited westward by the eastern 

 border of the Great Plains. Clearly certain of these distinctive lines 

 of Schistocerca have been established in our territory for a consider- 

 able time. Their history is tied to our area because, where found in 

 Mexico, most of them are Sonoran only. One of the lines in the 

 eastern and central United States, but hardly encroaching on our 

 territory, is broadly developed in Central and South America, 

 there having spawned one of the most destructive locusts of the 

 New World, the Parana locust {Schistocerca paranensis) of Argen- 

 tina and many other areas of South and Central America. 



The Vilernini are a most distinctive Neotropical assemblage of 

 a score or more genera, ranging from Argentina northward to 

 briefly north of the Mexican boundary, and are found in a variety 

 of habitats. Clematodes, the single genus in our region, is an apterous 

 thamophilous grasshopper, known only from the border regions of 

 western Texas, southern New Mexico, and Arizona, extending into 

 Mexico in several areas. It clearly has entered our territory from the 

 southward, and with us is probably more widely distributed in the 

 Lower Sonoran Life Zone than the records indicate (the secretive 

 habits of this grasshopper, which, among other situations, likes the 

 main stems of the intrusion-resisting cat-claw (Acacia), are largely 

 responsible for our limited knowledge of it). 



European students have broadly assumed that the great assem- 

 blage of the Melanoplini is basically a Eurasian group, with an 

 Angara background, and that its presence in the New World is 

 attributable to a relatively recent extension from the Old. Recently 

 this assumption has been challenged, on the basis of a relatively 

 critical analysis of the whole picture for the tribe. Little help can be 

 drawn from the fossil picture, as the total of such evidence to date 

 indicates the presence of two existing species of two genera in the 

 Pleistocene of Starunia in the Polish Carpathians. What we do 

 know is that in the New World members of the Melanoplini occur at 

 localities reaching from the Arctic Circle to at least south-central 



