DERMAPTERA AND ORTHOPTERA 287 



westward as far as Salt Lake City, Utah (possibly an accidental 

 introduction) and eastern New Mexico, and northward to southern 

 Manitoba, Saskatchewan, and Alberta, and the other, a more 

 southern race, extends west to central Texas. 



The subfamily Gryllinae is represented in western North America 

 by three genera, each with a very limited representation of species. 

 A single species, A. assimilis, of the virtually cosmopolitan genus 

 Acheta ranges over the greater part of the Neogaeic from Canada 

 to southern South America. It is now regarded by some as comprising 

 a group of probably physiological subspecies, as morphologically 

 these subsidiary elements intermingle to an inextricable degree, 

 and also they have no clearly defined gc§graphic allocations. 

 Members of the genus Gryllulus are known from the Tertiary of 

 both Europe and Argentina, and it is probable that in the New World 

 Gryllulus has had a very ancient history, but fossil evidence is very 

 limited. 



The genus Miogrylliis, which is represented in western North 

 America by two species, is clearly of Neotropical origin. Members 

 of the genus, including one of those found in North America, ran ge 

 southward to central Argentina, while others are more closely lim- 

 ited in the Neotropical Region. One of the North American species 

 is known in our territory only from a portion of the southwestern 

 United States, reaching from southern California to portions of 

 Texas and eastern Colorado. The second species, which is that also 

 of wide Neotropical distribution, occurs rather broadly over the 

 southeastern and central United States westward to Nebraska, 

 Kansas, Oklahoma, and central Texas. 



The genus GryUita is also Neotropical. The one species known in 

 the southwestern United States, has been found only in the 

 Baboquivari Mountains of Arizona, only a few miles from the 

 Mexican border, south of which undoubtedly the species also occurs. 

 Other members of the genus GryUita are known from more southern 

 Mexico, Central America, and the Greater (Cuba) and Lesser 

 (St. Vincent) Antilles, and its occurrence within our territory has 

 clearly been due to extension from a more austral center. 



The subfamily Oecanthinae is a cosmopolitan assemblage, includ- 

 ing the so-called tree crickets, because many of them frequent the 

 foliage of trees or bushes. The little we know about them as fossil 

 forms is that specifically unidentifiable remains have been found 



