394 PROCEEDINGS OF THE ACADEMY OF [Sept., 



Springs, Yellowstone National Park, Wyoming; altitude 7,000 feet, 

 Aug. 5, 1904. (M. Hebard.) [Hebard Collection.] 



Allied to C. undulatus (Thomas) and shastanus Bruner, but differing 

 from the former in the more robust form, the broader head, broader 

 heavier and less strongly sulcate frontal costa, larger eyes, slightly less 

 angulate caudal margin of the pronotum and in details of the coloration, 

 as the lighter and usually more variegated tegmina and pronotum and 

 the less distinct fuscous band and spur of the wing. From shastanus 

 it appears to differ in the heavier form and the structure of the first 

 subjacent radial vein. 



The form of the wing of this species is essentially that of C. undulatus, 

 and its closest relationship appears to be with that species. As 

 shastanus is not available for study, comparison can only be made with 

 descriptions, but the results of such comparisons seem sufficient to 

 separate the specimens in hand, especially when we consider the 

 peculiar structure of the first subjacent radial in the older species, 

 while in the new one here treated the structure of that region does not 

 differ materially from the type seen in undulatus. 



In coloration a number of specimens of this species bear a striking 

 superficial resemblance to C. carlinianus. 



Size medium; form quite robust; surface finely rugulose. Head 

 with the occiput gently but distinctly arched, the interocular region 

 no more elevated than the summits of the eyes and in width but little 

 less than the length of the eye; fastigium slightly declivent, forming 

 an obtuse angle with the face, nearly as wide as long, shallow, with the 

 median carina rather faint and the marginal carinse but little more 

 distinct; frontal costa broad, expanded between the antennae and 

 moderately constricted immediately ventrad of the ocellus, margins 

 carinate and nearly (c^) or not (?) reaching the clypeal margin, 

 broadly sulcate ventrad of the ocellus particularly in the male, strongly 

 punctate dorsad with a depressed area at the junction with the fasti- 

 gium; eyes moderately prominent, rather small, very broad ovoid in 

 shape; antennae slightly longer than the head and pronotum together, 

 somewhat depressed in the proximal section. Pronotum deplanate 

 dorsad, broad, distinctly expanded caudad; cephalic margin very 

 broadly and obtusely angulate; caudal margin rectangulate in the 

 male, obtuse-angulate in the female, the angle finely formed and little 

 rounded in either sex; lateral angles rounded and hardly marked on 

 the prozona, distinct and heavy shoulders present on the metazona; 

 median carina fine, little elevated, depressed at the principal sulcus, 

 prozona about half the length of the metazona; lateral lobes slightly 



