446 GEOLOGICAL SUEVEY OF THE TEEEITOEIES. 



Family II.— ACRIDID^. 



Sub-family Acridini^. 



First group. — Truxalini. 



Opomola, Erichs. 



0. hxichyptera,* Scudd., (Bost. Jour. Nat. Hist., YII, 454.) 

 Thos., (Proc. Piiil. Acad. Nat. Sci., 1871.) 



As Mr. Scudder at the time he described this species had but a 

 single male specimen, I have concluded to give a full description of 

 the unique female specimen I obtained in Wyoming Territory. 



Female. — ^Vertex carinated; elytra narrow, reaching the tip' of the 

 second abdominal segment. AntennsB broad, ensiform. Pale orange- 

 brown, with dusky points. 



Occiput convex, straight, not ascending, with a slight, shallow, longi- 

 tudinal depression each side, leaving a low, rounded, median ridge. Ver- 

 tex triangular, margins turned up, witha strong median carina, tbe three 

 meeting in front in a blunt point; length, in advance of the eyes, equal 

 to about one-third of the entire length of the head. The face tricarinate, 

 or rather quadricarinate, as the frontal ridge is so deeply sulcate that it 

 forms two distinct carinse, which meet at the vertex; all somewhat 

 divergent, and reaching the clypetis. Eyes oblong-ovate. Antennae 

 scarcely as long as the head and thorax, ensiform, flattened, and slightly 

 triquetrous. Pronotum about as long as the head, tricarinate; sides 

 parallel ; only the posterior transverse impression distinct on the disk, 

 situate a little behind the middle. Elytra lanceolate, narrow, reaching 

 the tip of the second abdominal segment. Wings narrow, minute, about 

 half as long as the elytra. Abdomen long, slender, and somewhat cylin- 

 drical, slightly carinated. The four anterior legs slender; posterior 

 femora, slender, straight, not as long as the abdomen ; posterior tibiee 

 slender, nearly cylindrical, somewhat hairy at the apex. Prosternal 

 point is only a blunt tubercle. 



Color, (dried, after long immersion in alcohol.) — Pale orange-brown, 

 without distinct spots or markings, but with numerous minute dusky 

 points. The antennae are iDurplish brown ; the vertex, legs, and abdo- 

 men tinged with the same color. Spines of the posterior tibiae, abdom- 

 inal appendages, and tarsal claws tipped with black. When living, 

 the only specimen I have seeu in the perfect state, was of a uniform 

 grayish-brown ; length, 1.5 inches. 



My specimen was obtained near the ruins of old Fort Casper, on the 

 North Platte Eiver, Wyoming Territory, August 22. I have some 

 larvae and pupae obtained in Cache Valley, Utah, which possibly belong 

 to this species. 



0. Wyomingensis, Thos. 



Syu., Mesops Wyomingensis, (Proc. Phil. Acad. Nat. Sci., 1871.) 



Small, slender, and cylindrical; elytra reaching the fifth abdominal 

 segment; abdomen of the male terminating in an acute prolongation. 

 Pale green, sometimes varied with reddish, immaculate. 



^ This specific name is twice used; the Acridium (Pyrgomorpha) iracliyptera, 

 Haan, (Verz. Nat, Gesch. Ned. lud. Bez. Ins., 150,) having been referred by Walker to 

 Oj)omoJa, becomes 0. Iracliyptera, but Mr. Scudder's species received the name first, 

 hence must stand, and that of Walker changed. (See Walk. Cat. Dermop. Salt., Ill, 

 514.) 



