GEOLOGICAL SURVEY OF THE TERRITORIES. 271 



Habitat: From Cheynne south to Eaton Mountains, on the plains and 

 foothills at the eastern base of the range. 



When living this is a very pretty insect, the dark stripes being mar- 

 gined by red, which fades when immersed in alcohol, the black also be- 

 coming paler and assuming a purplish cast. This may possibly belong 

 to JDactylotum, Charp, but I am not fully acquainted with the characters 

 of that genus. 



(Mutici.) 



ERACHYPEPLUS, (CHARP.) 



As Charpentier, at the time he established this genus, failed to give 

 its characters, and the description of Girard is so short arid deficient, I 

 give, from a large number of specimens, what I conceive to be the dis- 

 tinguishing characteristics. 



Generic characters: Body very robust, acridoid. Occiput' broad, 

 convex, smooth; vertex margined; frontal ridge broad, short, slightly 

 sulcate, expanding below; lateral carinas distinct, with a sulcus behind 

 each ; antenna! foveolas deep, oblong ; cheeks prominent. Pronotnm 

 large, elongate, tricarinate; carina distinct, continuous; widest below, 

 expanding posteriorly, sides straight, generally chagrined above, with 

 the sides glabrous ; no transverse incisions on the dorsum ; anterior 

 margin rounded, extending slightly on the head; posterior margin 

 round. Elytra and wings rudimentary, (in the known species.) Legs 

 very robust; posterior femora long as the abdomen, swollen; tibiae 

 strongly spined nearly the entire length. Antennas filiform, joints dis- 

 tinct ; long as the head and thorax. Sub-anal plate of the male tumid 

 entire ; cerci very short ; female appendages stout, broad. Palpi short, 

 joints all enlarged at the tip ; the three outer joints of the maxillary 

 palpi nearly equal, the ultimate a little the longest. Presternum neither 

 spined nor tuberculate. Abdomen somewhat compressed, carinated 

 above. A well-marked and distinct genus. 



B. magnus, Girard. (Marcy's Expl. Eed River of Lous., p. 260, PI. 

 XV, figs. 1-4.)— This ponderous species is easily recognized by the 

 figures referred to, but the description is quite deficient ; therefore, to 

 aid future investigations, I give it more minutely. 



(Siccus.) Yellow, spotted with brown. Occiput convex, very slightly 

 scabrous, an indistinct line running along the middle to the vertex, a 

 few fine shallow punctures visible ; the elevated margins of the vertex 

 meet in about a right angle at the front ; frontal ridge, although nar- 

 row above and gradually expanding as it descends, is not narrowed 

 opposite the antennas; margins distinct, obtuse ; sulcus shallow, expand- 

 ing and fading below, punctured. Pronotum with three distinct, con- 

 tinuous piceous carinas ; dorsum strongly chagrined, yellowish, with aque- 

 ous luster ; sometimes, especially in the females, there is a yellow line 

 along each margin of the dorsum ; sides purplish at the upper angles, 

 yellowish below. Elytra ovate, reaching the third abdominal segment ; 

 nerves longitudinal, slightly branching near the extremity; Ught brown, 

 spotted with black. Wings very small, yellow. Abdomen marked with 

 a brown spot each side of each segment ; each segment is also margined 

 with a row of white dots. Legs as described by Girard. 



Dimensions: Length, (female,) 2 inches; pronotum, .55 inch ; elytra, 

 .3 inch ; femora, 1.25 inch. Males about one-fourth less. Size varies 

 considerably. . 



Habitat : From Fort Laramie south to Santa Fe. The green and 

 brown varieties were both observed; but after being immersed for some 



