38 
IOWA ACADEMY OF SCIENCES. 
pies of this, and it is also found in T. gothica , occatoria , 
dohrni, bifida and tripunctata. The darkening up 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 Pocky 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 prominent, 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 4 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: i 
General form, cylindrical, usually elongate Tettigoniina 
General form, broadly oval, or flatfish, usually compact. .Gyponnia 
The present paper deals only with the first group, exclud- 
ing some forms like Euacanthus and its allies, which are 
usually placed here. 
SUB-FAMILY TETTIGONIINA. 
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 deflexed. 
