150 BULLETIN UNIVERSITY OF MONTANA. 



AFRANIUS' DUSKY-WING, Thanaos afranius, Lintner. 



Fig. 110. Thanaos afranius. 



Butterfly The hind wings on the upper side in the male are almost 

 solid black, the fringes paler. On the underside there is a double row of 

 light spots along the margin of the hind wing in both sexes. On the 

 upper side the female is generally lighter in color than the male. 



Early Stages Unknown. 



Distribution Common in Arizona. Given in Dyar's list. We have 

 not taken it. One specimen from Bozeman, one from Helena, and one 

 from unknown locality we have referred to this species. 

 Subfamily PAMPHILINAE. 



In this subfamily is included the greater number of our smaller 

 skippers; however, some of the species are larger in size than many of the 

 Hesperiinae. All of our tawny skippers belong to this subfamily, as 

 well as some black or dark-brown species. The antennae usually have 

 a stout club, with a short recurved tip; sometimes this tip is wanting. 

 Fig. 112 shows plainly the venation. In the majority of our species the 

 males can be recognized by the brand; this is a conspicuous dark patch 

 crossing the disk of the fore wings obliquely. This brand is a compli- 

 cated organ, composed of tubular scales, the androconia, that are the out- 

 lets of scent glands, and of other scales of various shapes; the brand is 

 wanting in some species. 



The Pamphilinae are difficult to study, owing to the slight differences 

 in allied species. Either sex, moreover, resembles the same sex of other 

 species much more closely than it does the opposite sex of the same 

 species; and the difficulty is further augmented from the fact that in 

 several species there are two distinct forms of females which differ from 

 each other more than either does from the females of certain other 

 species. These species have three forms, one male and two female. 

 Key to Genera. 



1. Antennae with the point of the club absent; end obtuse 2. 

 Antennae with the point of the club present; end sharp 4. 



2. Fore wings of male with a linear stigma. 



Fore wings of male without a linear stigma 3. 



3 Under surface of hind wings with silvery whites pots Pamphila 



Under surface of hind wings without silvery white spots Oarisma 

 4. Antennae with the point of the club short, less than width of club 5. 



Antennae with point of club long, equal to or greater than the middle 

 of club 9. 



