122 



that given by Dyar, and one that would include both sexes appears to 

 be found in the palpi ; in Pyrgus they are only slightly upturned and 

 the clothing under a strong lense is seen to be rather even and com- 

 posed largely of scales with a few hairs of equal length intermingled ; 

 in Hesperia the palpi are strongly upturned and very heavily and 

 roughly clothed underneath with long hairs, the scales being confined 

 to the lateral basal portion ; syrichtus, philetas, and tessellata are quite 

 typical of Pyrgas and centaurcae of Hesperia. 



H. xanthus Edw. (PI. X, Fig. 13). 



In the Edwards' Collection at Pittsburg are four specimens, all 

 from S. Colo. (Morr.), labelled xanthus; 1 $ and 2 ? 's of these belong 

 to a larger species than the remaining one and would seem by the 

 description and measurement given (4/5 in.) to be the true xanthus 

 and presumably the types. The smaller species (PI. X, Fig. 14) is 

 probably Oberthur's macdunnoughi (1914, Et. de Lep. Comp. IX, (2) 

 86) so that in any case the name xanthus would be automatically 

 restricted to the large forms ; there is no costal fold in the $ 's of mac- 

 dunnoughi but the structure is otherwise identical with that of malvae. 

 We figure our conception of both species which are very closely allied. 



Heliopetes nivella Mab. 



We have a specimen of this species from Brownsville, Texas. 

 It is close to tnacaira Reak. but larger and with the dark border of 

 secondaries on under side more broken and containing white spots ; 

 the upper side of secondaries also has black marginal markings. This 

 species is new to our fauna. 



Genus Thanaos Bdv. 



Tutt's action (Brit. Butt. I, 85, 260) in sinking Thanaos as a 

 synonym of Nisoniades on the ground that the type species of both is 

 tages L., is incorrect. Stephens' action in 1834 and 1850 in placing 

 tages as sole species under Nisoniades cannot, for the same reasons as 

 we have already stated under Pyrgus, be regarded as a restriction or 

 a fixation of the type. The first definite type fixation that we know 

 of for Nisoniades is by Scudder in 1875 (Hist. Sketch, p. 228) who 

 gives bromius Stoll as type; this action is valid and has been followed 

 by Watson, Godman & Salvin, and Mabille. 



T. callidus Grinnell. 



Lacustra Wright is made a synonym of this species by Grinnell 

 (1905, Ent. News, XVI, 339). Dyar (1905, Jour. N. Y. Ent. Soc. 



