98 



IOWA STUDIES IN NATURAL HISTORY 



al specimens show a faint trace of spots on the upper surface of the pri- 

 maries, and frequently the ground color is darker. 



2. MASTOR BELLUS 



Pamphila helium Edw., Papilio iv, 57, 1884. 

 Biol. Cent. -Am., Ehop. ii, 568, pi. 100, f. 36, $ gen., 1900. 

 Skinner, Ent. News xi, pi. ii, ff. 11, 12, 1900. 

 Kellogg, Am. Ins. pi. ix, ff. 11, 12, 1904. 

 Wright, Butt. W. Coast 247, pi. xxxi, f. 443, 1905. 

 Arizona, May to July, 



3. MASTOR PHYLACE 



Pamphila phylace Edw., Field and Forest iii, 117, 1878. 

 Arizona, Colorado, New Mexico; June. 



4. MASTOR OSLARI 



Pamphila oslari Skinner, Ent. News x, 112, 1899. 



New Mexico, Arizona, Colorado; April, June to Augvist. 



Oslari is usually pale fuscous above, but occasionally a series will show 

 some yellow fulvous scales on the disk of the primaries and a faint trace 

 of indefinite spots such as are always present in Aj, nanno. Such speci- 

 mens may be separated from nanno by the gray under surface of the sec- 

 ondaries with vague pale spots instead of small sharp ones. 



Genus AMBLYSCIRTES Scudder 

 Amblyscirtes Scud., Syst. Rev. 54, (75), 1872. Type Hesperia 



vialis. Edw. 

 Stomyles Scud., op. cit. 55 (76). Type Pyrgus textor Hbn. 



Palpi large, upturned; second 

 joint with shaggy vestiture; third 

 slender, smooth, vertical; almost as 

 long as second except in nanno. An- 

 tennae moderate; club large; apicu- 

 lus longer than thickness of club. 

 Primaries in most species similar in 

 the two sexes, less apically produced 

 than in the related genera; costa 

 flattened ; apex rounded-rectangu- 

 lar; outer margin strongly rounded 

 except toward anal angle ; cell about 

 three-fifths 'as long as wing ; discocel- 

 Fig. 29. AmUyscirtes vMis Edw. a. lulars vcry wcak and only slightly 



Club of antenna, .b^ Palpus, c. oblique; VCiu 5 WCakly CUrVCd 



