HESPERIOIDEA OF AMERICA 57 



Chaerephon in Group B. I regard this as furnishing the phylo- 

 genetic basis for the separation of Group A from the Hesper- 

 iinae, which makes it necessarj^ to explain their resemblance by 

 parallel or convergent evolution. 



In place of the two groups into which the Pamphilinae have 

 commonly been divided I believe that a modification of the sys- 

 tem used in the Biologia will be of greater convenience. I have 

 therefore divided our fauna into four groups which are char- 

 acterized as follows: 



Group A. Palpi porrect. Vein 5 of primaries straight, in- 

 tennediate between 4 and 6 ; cell less than two-thirds as long as 

 wing. Club of antennae blunt. Carterocephalus and Biitleria. 



Group B. Palpi upturned ; third joint long and slender. An- 

 tennae short ; club blunt. Vein 5 of primaries cun^ed slightly 

 toward 4 at base. Cell less than two-thirds as long as wing. 

 Ancyloxypha, Oansmu, Adopaea and Copaeodes. 



Group C. Palpi appressed or oblique; third joint moderate 

 or small, long in Amhlyscirtes. Antennae with a slender api- 

 culus in most genera. Vein 5 of primaries cun^ed at base, us- 

 ually arising much nearer to 4 than to 6. Cell less than two- 

 thirds as long as wing. All North American genera not includ- 

 ed in A, B and D. 



Group D. Palpi closelj^ appressed, smoothly and deeply 

 sca.led; third joint small. Club of antennae stout, with a fine, 

 abruptly constricted apiculus. Vein 5 arising much nearer to 

 4 ; cell about two-thirds as long as wing and with at least a rudi- 

 ment of a recurrent vein. Thespieus, Calpodes and Prenes. 



GROUP A 

 Key to the genera 



Hind tibiae with one pair of spurs Carterocephalus 



Hind tibiae with two pairs of spurs Butleria 



Genus CARTEROCEPHALUS Lederer 

 Carterooepluilus Led., Verb. z.-b. Ges. Wien n, 26, 49, 1852. 



Type : Papilio paI<i€mo)i Pallas. 



Second joint of palpi oblique, loosely clothed with long hairs; 

 third slender, moderately long, enveloped by hairs of second. 

 Antennae less than one-half as long as primaries; club large, 



