NATURAL SCIENCES OF PHILADELPHIA. 153 



the middle joint being rather longer in proportion to the others 

 than usual. Prosternal point quite short and blunt, more so in 

 the female than in the male. Mesosternum convex, with a sharp 

 indentation running lengthwise on each side. 



Color (dried after long immersion in alcohol). Pale greenish- 

 yellow, immaculate. Antennae dull ash golor, darkest along the 

 exterior margin Spines of the posterior tibia and tarsal claws 

 tipped with black. When living, the female is of a uniform pea- 

 green color. 



Male. Differs from the female as follows: Is much smaller 

 and of more slender proportions. The vertex more pointed and 

 the margins slightly elevated. Face rather more oblique, being 

 almost horizontal. Abdomen terminating with a long-pointed 

 extension bent slightly upward at the tip, about equal in length 

 to the head. El^'tra and wings same proportional length as in 

 the female. Antennoe, face, vertex, occiput, pronotum, posterior 

 femora, and abdominal appendage a pale carneous red ; a white 

 stripe runs from tlie lower border of the eye along the lower edge 

 of the face and pronotum to the base of the middle legs. This 

 description of the male marks the extreme variation from the 

 female, those of immediate shades being common. 



Found along the east base of the Black Hills of Wj-oming, in 

 the vicinity of Cottonwood Creek, August, 1870. Taken in the 

 grass}^ creek bottoms. 



Dimensions. Female — length 1.1 inch ; male, .9 inch. 



I have placed this species in Mesops^ to which it appears to 

 belong from the incomplete generic description of Serville, who 

 had only one imperfect specimen, which had the apex of the abdo- 

 men wanting. Walker (Cat. Dermap., III. 501) names another 

 species of this genus — 31. carinatus — as found in the United States, 

 but speaks of the sheaths of the oviduct of the female as being 

 lanceolate. 



]\fote. — Two errors occur in my paper published in the Proceedings July, 

 1870, which should be corrected. 



B. nigrum, Thos., should be B. nubilum, Thos. 

 Syn. Gryllus nuMlus, Say. 

 Oed. pruinosa, Thos., should be Oed. trifasciata, Thos. 

 Syn. Gryllus trifasciatus. Say. 



The descriptions are proper, aud may stand, as the original descriptions 

 of Say are very short and incomplete. The corrections were forwarded 

 before publication, but failed to reach their destination. • 



1871.] PART IL— 11 



