38 IOWA ACADEMY OF SCIENCES. 



pies of this, and it is also found in T. (/ofhica^occatoria, 

 QMlohrni^ bifida 2i\\^ iripundcda. The darkening np of spe- 

 cies in their northern limits is also intensified in this group, 

 and, as usual in the Jassoidea, specimens from the Pacific 

 Coast, especially in the northern part, are considerably 

 larger than those from the Mississippi Valley and farther 

 east. Those from the Rocky Mountains and the adjacent 

 plains are somewhat intermediate, grading off on either 

 hand. 



The gentalia are of less importance in this group, as a 

 whole, than in many others, but, as in some species, they 

 are strikingly distinctive and in most cases they furnish 

 good characters in one or both sexes they have been made 

 rather p7-ominent, in striking contrast to the treatment of 

 other authors. The venation of the elyta has been found 

 to be of considerable service in defining groups of species, 

 and in some instances' furnishing specific characters. 



The Tettigonidae are at once separated from the rest of 

 the Jassoidea by the ocelli being situated on the disc of 

 the vertex. They are usually divided into two groups, on 

 the general shape of the body, as follows: 



(reneral form, cylindrical, usually elongate Tettigoniina '^ 



General form, broadly oval, or flattish. usually compact. .Gyponnia O K 



The present paper deals only with the first group, exclud- 

 ing some forms \\ke/Euacanthns and its allies, which are 

 usually placed here. 



C> SUB-FAMILY TETTICON UNA. ^ 



The following key to the genera while emphasizing the 

 fundamental characters separating the genera, as a whole, 

 makes use of other and minor characters that are of value 

 in separating our forms, but that might be untenable in a 

 larger series: 



^ KEY TO THE GENERA. 

 A. Antennal sockets usually overhung by a distinct ledge, the 

 anterior extremity of which is deflexed and roundingly trun- 

 cate. Anterior tibiae sulcate above or dilated at the extrem- 

 ity. Elytra narrow, not covering lateral margin of abdominal 

 tergum. Head and pronotum usually detiexed. 



