44 



IOWA STUDIES IN NATURAL HISTORY 



in generic distinctions. Bolla was separated from Pholisora by 

 Mabille on the basis of the more pointed club of the antennae. 

 Dyar associates Hesperopsis in his description with Hesperia 

 instead of Pholisora and calls attention to the long palpi, es- 

 pecially the long third joint, and the absence of the costal fold. 

 I have bleached and mounted structures of alpheus, Hoy a, catul- 

 lus, ceos and hayhurstii and have found the following things to 

 be true : In alpheus the third joint of the palpi is about three- 

 fifths as long as the second and both are slender; the vestiture 

 of the third joint makes it appear about twice as long as it really 



Fig. 13. Pholisora. Palpi: a. alpheus, b. libya, c. catullus, d. ceos, e. hay- 

 hurstii. Antennal clubs: f. libya, g. catullus, h. ceos, i. hayhurstii,* j. Neur- 

 ation of hayhurstii, k. and 1. Outer margins of wings of ceos and catullus 



is. Libya, associated with alpheus, has the third joint relative- 

 ly shorter, both second and third thicker, the vestiture of the 

 third similar and that of the second deeper. The entire ap- 

 pendage looks more like the palpus of catullus than alpheus. 

 The eleventh vein of the primaries of alpheus arises well before 

 the middle of the cell, while in all of the other species it arises 

 near the middle, usually slightly beyond. Ceos differs from 

 catullus in the relatively longer third palpal point and thicker 

 second, and in the short vestiture of the third. In the shape of 

 the wings it is intermediate between catullus and Jiayhurstn and 

 farthest removed from alpheus. The antennal club is thickest in 

 alpheus and most slender in ceos, but if the same aspect be com- 

 pared the species are seen to differ but slightly. From this it 



