284 J. A. G. REHN 



genus, it evidently has evolved in our liemisphere, probably within 

 the broad limits of the semi-arid and arid Sonoran life center. 



In the subfamily Rhaphidophorinae one definitely placeable 

 genus, Prorhaphidophora, is known from as far back as the Lower 

 Oligocene amber of East Prussia. Existing members of the subfamily 

 are wingless, usually nocturnal, and many are cavern-dwelling. 

 More than a score of genera are represented in Europe, Asia, North 

 America, Australia, and New Zealand. Only one of the thirteen 

 genera in North America occurs outside of this continent, and this 

 genus, Tachycines, is a rather recent accidental introduction from 

 eastern Asia, now well established under protected conditions in the 

 eastern and central United States as far west as the Dakotas and 

 Colorado. The remaining twelve North American genera are all 

 endemic. They are related to two genera occurring to the southward, 

 Phoheropiis in the mountains of Central America and Argytes on the 

 Pacific side of the Mexican Plateau. It is clearly evident that this 

 assemblage of more than one hundred species, which Hubbell, who 

 has done detailed work on it, regards as the tribe Ceuthophilini, 

 has as a whole developed in North America, and to a lesser 

 degree in adjacent Mexico and northern Central America. 



Three of the genera of the Ceuthophilini are western North 

 American endemics: Tropidischia, which ranges northward in Pacific 

 territory to British Columbia; Rhachocnemis , which is known only 

 from the unique type from "California"; and Gammarotettix, which 

 occurs in various non-desert parts of California, with one species 

 also occurring about the headwaters of the Gila River in eastern 

 Arizona. The genus Pristoceiithophilus occurs solely in western 

 North America from British Columbia to north-central Mexico, 

 often in montane localities. Styracosceles is limited to areas of the 

 southwestern United States east to Colorado. The very unusual 

 recently described genus Salishella is known only from the mountains 

 of north-central Idaho and the Olympics of Washington. It is a type 

 of marked specialization, that probably developed in a north- 

 western center, as it has no close relatives in any surrounding 

 territory. The genera Daihiniodes and Daihiniella are definitely 

 Sonoran in their distribution. Ammobaenetes has a similar pattern, 

 in sand areas. The genus Udeopsylla is truly Campestran. Daihinia 

 has a similar range, but reaches into adjacent Cordilleran territory. 

 The widely spread genus Ceuthophilus is represented by some scores 



