DERMAPTERA AND ORTHOPTERA 293 



distributed. In our limits it occurs from central Texas and eastern 

 and northern New Mexico to Needles and Calexico, California. 



Within our territory the subfamily Oligonicinae is represented 

 only by the genus Oligomcella, which, like the subfamily, is clearly 

 of Neotropical derivation. The two species of the genus within our 

 limits are known there only from Texas and southern Arizona. 

 One, which elsewhere has a broad distribution in the southeastern 

 United States, extends across Texas to its trans-Pecos section. 

 The other, an intrusive from Mexico, is known only from extreme 

 southern Texas and southern Arizona. 



The subfamily Vatinae, a Neotropical assemblage, includes two 

 genera that narrowly enter our territory from northern Mexico. 

 Both also range broadly over Central and South America. One of 

 these genera, Phyllovales, has a single species of much broader 

 distribution occurring with us only in extreme southern Texas, and 

 the other, Vates, is represented by one endemic species in certain 

 mountain areas of extreme southern Arizona. 



The subfamily Photininae, all the other members of which are 

 entirely Neotropical, is represented in our territory by one species 

 of the striking genus Brunneria, which ranges from the grass 

 prairie country of east-central Texas to central North Carolina. 

 The North American species of Brunneria, B. borealis, is partheno- 

 genetic — no male has ever been taken, although hundreds of females 

 have been secured at a considerable number of localities. The genus 

 has a discontinuous distribution; no member other than B. borealis 

 is known from north of central Brazil, Paraguay, and northern 

 Argentina, where other species occur with the male sex as frequent 

 as the female. All members of the genus are strictly grassland forms, 

 and the postulate that what we see is a reflection of the far greater 

 extent and former broader prevalence of grasslands in the Pliocene, 

 with their marked restriction in the more humid Pleistocene, 

 with the correlated augmentation of lowland forests in that period 

 in the tropics, seems to be the logical explanation. A theory of 

 drift across the Caribbean has been advanced to explain the sit- 

 uation, but the genus does not occur in northern South America as 

 far as known, in fact at no place between Texas and territory much 

 south of the Amazon. Somewhat parallel conditions exist in other 

 genera of the Orthoptera which are grassland forms, and for which 

 the same postulate seems applicable. 



