288 J. A. G. REHN 



in the Lower Oligocene and Upper Miocene of Germany and France. 

 In the present world fauna members of the subfamily are to be found 

 wherever their chosen environment exists in virtually all parts of 

 the temperate and tropical regions. They are represented in the 

 Nearctic fauna by two genera, one of which Neoxabea occurs in 

 Nearctica only in the eastern part of North America, but other 

 members of that genus are well distributed over the Neotropical 

 Region south of Mexico, as far as northern Argentina. The other 

 genus, Oecanthus, is cosmopolitan over the temperate and tropical 

 parts of the world, but its greatest concentration of species is in 

 North America. A definite area of marked specific differentiation is 

 in eastern North America, and three of the four specific lines of the 

 genus represented in western North America, are there at the 

 extreme western limits of distribution of more widely spread and 

 dominant eastern species of the genus. The status of at least one of 

 the endemic species reported from the western United States is at 

 present uncertain, but another one, 0. calif ornicus, is clearly autoch- 

 thonous and doubtless will be found to extend into northern 

 Mexico. 



The subfamily Pentacentrinae is an aberrant group of small 

 crickets broadly distributed within the tropics. A single genus, 

 Trigonidomimus , enters our territory in central Texas, while to the 

 southward it ranges across Mexico and Central America to Panama. 

 The other genera of the subfamily are known from Brazil, Cuba, 

 Madagascar, West Africa, Ceylon, and Formosa. Clearly Trigoni- 

 domimus entered our territory from the Neotropical Region. No fossil 

 members of the subfamily are known. 



A single genus, Anaxipha, of the subfamily Trigonidiinae is 

 represented within western North America by one species which is 

 largely eastern in its distribution, reaching to central Texas and to 

 the eastern parts of Nebraska and Kansas. The subfamily is found in 

 virtually all the warmer parts of the earth, on foliage or in low 

 plant cover, and is also represented in Pleistocene or post-Pleisto- 

 cene African copal. The genus Anaxipha is entirely New World 

 in its distribution, with many tropical American species. A secondary 

 evolutionary center for the subfamily and also for the genus Anaxi- 

 pha apparently developed in the southeastern United States, 

 where several other distinctive genera of the subfamily occur, one of 

 which is entirely restricted to that area. 



