147 



black line on the occiput ; lateral carinas of the lace and margins of the frontal 

 costa black. Female appendages tipped with red. Posterior legs are colored 

 as follows : Femora dark olive-green to black, a pale-yellowish stripe along 

 the lower exterior margin, the lower, outer carina olive-red, channel black, 

 inner portion yellow, with two oblique, black bands ; tibije black at the base, 

 patella red, upper part of the exterior dark-blue, changing downward to pur- 

 plish, vermilion at the apex, inside yellow ; spines yellowish at base, tipped 

 with black ; tarsi red above, whitish beneath. The other tibiae colored as the 

 posterior one. 



Dried specimens, after immersion in alcohol, are about as follows : Dor- 

 sum dark reddish-brown ; head and face paler, black markings of the carinse 

 remaining. Lower portions of the sides of the pronotum a shining, yellowish 

 color. A pale line along the median carina of the abdomen. Disk of the 

 posterior femora dark-brown ; upper and lower exterior margins yellow ; 

 channel beneath black ; upper carina black ; two bands and spot at the base 

 and apex internally, black. Patella (or tubercle at base of the tibiee) yellow, 

 and a na"rrow, black band just below this; remainder of the tibiae brownish- 

 purple. Beneath dull-yellow. 



Dimensions. — 9 Length, 1.05 to 1.12 inches; posterior femora, 0.5 inch; 

 posterior'tibise, 0.43 inch. $ Length, 0.76 inch. 



Found on the dividing range of the Rocky Mountains between Idaho 

 and Southern Montana, and a ridge 8,000 feet above the level of the sea, 

 about forty miles southwest of Virginia City, Montana (Thomas). 



It appears to be closely allied to Dactylotum, Charp., but that author 

 has not given the generic characters with sufficient accuracy for me to decide 

 the point. I have given the characters somewhat iully to enable those who 

 have not specimens to judge as to its proper generic position. 



P. pacta, Thos., Proc. Acad. Nat. Sci. Phil., 1870, 78.— Geol. Surv. Terr., 



1870, 270. 



Medium size; body elongate, sub-cylindrical. Vertex deflexed, flat, and 

 narrow between the eyes, suddenly expanding in front of them, this advanced 

 portion transverse and triangular; the frontal costa somewhat convex, with a 

 very slight depression at the ocellus. Eyes somewhat large, prominent, and 

 oval. Antennas filiform, nearly as long as the head and thorax. Pronotum 

 sub-cylindrical, dorsal portion cylindrical, without cariiiic ; sides parallel 



