32 GUIDE TO ORTHOPTERA 



siderably oblique ; frontal costa not 

 sharply acuminate above and scarcely 

 sulcate at any point. Psoloessa Scudcler. 



Excepting Mermiria, the first thirteen of these genera, as well 

 as Acentetus, Amblytropidia, Clinocephalus, Phlibostroma, Plec- 

 trotettix and Bruneria, or more than half the total, are only 

 known in our country by single species ; the others have from 

 two to six each, and Orphula probably more than that. Orphula 

 appears to be the only genus spread over the entire country ; some 

 are so far known only from a single state, as Rhadinotatum 

 and Pedeticum from Florida, Acentetus from Colorado, Acrocara 

 from Idaho and Pedioscirtetes from Nevada. Clinocephalus is 

 confined to the Atlantic States, Tryxalis (Metaleptea Brunner) 

 to the region east of the Great Plains ; Psoloessa is known only 

 from the extreme south, from Texas westward, Achurum and 

 Bootettix in the extreme southwest. The great plains east of 

 the Rocky Mts. are characterized by Opeia, Phlibostroma (Beta 

 Brunner), Boopedon and Acrolophitus, while they share with 

 the region to the west of them, as far as the Sierras or even 

 the coast, the genera Stirapleura (Pseudostauronotus Brunner), 

 Alpha, Amphitornus, Mermiria, Aulocara (Oedocara Scudder, 

 Coloradella Brunner) and Ageneotettix (Eremnus McNeill). 

 Gomphocerus is found in the same region, but only in its northern 

 portions. Chloealtis, Dichromorpha, Mecostethus and Steno- 

 bothrus are also found in the northern half of our country (and 

 in Canada) from the Atlantic to the Rocky Mts. or even to the 

 Sierras, while an equivalent southern district is inhabited by 

 Amblytropidia, Syrbula and Eritettix. Finally, the genera Liguro- 

 tettix, Gymnes, Xapaia, Plectrotettix (Plectrophorus McNeill), 

 Bruneria (Brunneria McNeill) and Eupnigodes (Pnigodes Mc- 

 Neill) are confined to the Pacific coast. 



OEDIPODINAE. 



This is one of the prevailing groups of Acridiidae in the United 

 States, and especially in the western half of the continent. Two 

 of the tribes occur, the Thrincini being unknown. Our genera 

 are in large part indigenous. 



