260 J. A. G. REHN 



Ethiopian and Malagasian and the Neotropical. One of the most 

 aberrant subfamiHes, hmited to AustraHa and Tasmania, in a num- 

 ber of respects approaches the exceedingly distinctive and endemic 

 Neotropical family Proscopiidae. No member of the Eumastacidae 

 extends into the Palearctic Region except in elevated areas of Central 

 Asia and in Japan, and the family is absent from the Pacific Islands 

 east of New Guinea and from New Zealand, as well as from Chile 

 and southern Argentina. Three genera are known from two of the 

 greater Antilles (Cuba and Hispaniola), but the family has not been 

 taken in any of the others. 



The southwestern United States is the only part of North America 

 in which members of the family now occur. They represent five gen- 

 era of two very different subfamilies, both of which, as far as present 

 knowledge indicates, are endemic within the area. One of these 

 subfamilies, the Tanaocerinae, comprising the genera Tanaoceriis 

 and Mohavacris, is localized in certain semi-arid and arid mountains 

 and adjacent desert areas of southern California and southern 

 Nevada, except for one species of Tanaocerus that is also found in 

 northern Baja California. This subfamily in many respects is one 

 of the most distinctive assemblages in the superfamily Acridoidea, 

 the antennae being the longest in any members of that extensive 

 and varied aggregation known as the "short-horned" grasshoppers. 

 The Tanaocerinae, which has been regarded by some as of family 

 rank, and even considered by one student to represent two families, 

 is clearly a Nearctic autochthon, which because of its combination 

 of unusual characters certainly may be inferred to have developed 

 a considerable time in the past. It is in a number of respects probably 

 the most strikingly isolated section of the whole family, and it 

 apparently developed from one of its ancestral lines. The other 

 Nearctic subfamily, the Morseinae, comprising the three genera 

 Morsea, Eumorsea, and Psychomastax, is a cohesive assemblage 

 known only from Arizona, extreme southwestern Utah, southern 

 Nevada, and areas of southern and coastal California north to Mt. 

 Tamalpais. Morsea, the most widely distributed of the three, occurs 

 in its preferred habitat over the greater part of the full range of the 

 subfamily, although it is not known from southern Arizona. Psycho- 

 mastax is peculiar to mountain areas of southern California and 

 southern Nevada, reaching northward along the eastern slope of the 

 Sierra Nevadas, occurring also in the White Mountain section of the 



