144 



tropical America; and to this group also belong the injurious species of the 

 Eastern States {Caloptenus fe?nu7--rubrum), and the destructive, migratory 

 species of the West {Caloptenus spretus). Most of the species possess ample 

 wings, yet there are many which have them aborted, and some are wholly 

 without wings or elytra. 



It is represented in the United States by but seven genera, which I 

 have arranged in the following order : 



Pezotettix, Platyphyma, Ommatolampis, Caloptenus, Chromacris, Acri- 

 dium, Tropidacris. 



It is true that an examination of the species will satisfy any one that 

 here I have not maintained my descending series ; but I have been com- 

 pelled, in one sense, to vary my plan, in order to bring as near together as 

 possible the closely-allied forms. In fact, the order in which I place the 

 genera in this group may be considered ascending, and the relations may 

 be represented thus (Tryxalini at the head and Tettiginse at the foot) : 



CEdipoda, &c., to 

 Boopedon, Oxycoryjihus, 





Brachypeplus, 



dp' — Pezotettix, Tryxalini. 



% Platyphyma, 



Ommatolampis, 



Caloptenus, Xiphocerini^ 



Acridium, &c., to 



Locustini. 



As a matter of course, this applies only to the genera found in the United 

 States ; if the exotic genera w^ere introduced, the transition would probably 

 be more apparciit, yet the difficulty in arranging the Tcttiginas would not be 

 entirely overcome. 



Synoptical table of the genera. 



A. Front border of the pronotum notched Chromacris, 



A A. Front border of the pronotum entire : 



a. The dorsum of the pronotum more or less arched from the sides ; 

 no lateral carina; ; extremity of the male abdomen not swollen : 



h. Pronotum crested, species very large Tropidacris. 



bh. Median carina of the pronotum not crested Acridium. 



