HESPERIOIDEA OF AMERICA 7 



ly with two pairs of spurs; front legs normal. Frenulum 

 present in many families. Venation of primaries general- 

 ized or characteristically specialized. Pupa loose in cocoon, 

 earthen cell or plant tissues. Superfamilies Sphingoidea, 

 Saturnioidea, Bombycoidea and Tineoidea. 

 Series Rhopalocera. Antennae usually strongly clavate ; nev- 

 er pectinate or ciliate. 



Superfamily Hesperioidea : Pupa suspended in a slight 

 cocoon. Hind tibiae rarely with less than two pairs of 

 spurs; front legs normal. Frenulum absent. Primaries 

 with twelve veins, all free. (All five branches of radius 

 present and from cell according to Comstock's system.) 

 Superfamily Papilionoidea : Pupa naked, usually suspend- 

 ed from silken attachments and specialized for conceal- 

 ment. Hind tibiae with only the terminal pair of spurs; 

 front legs in higher families greatly reduced. Frenulum 

 absent. Primaries with less than twelve veins or with 

 some stalked. 

 In the Hesperioidea we have two families, the Hesperiidae and 

 Megathymidae. The second includes only the genera Megathy- 

 mus and Aegiale, and is equivalent to the subfamily of other 

 writers. The first includes all other skippers. The Megathymi- 

 dae are very closely related to the Pamphilinae, and some stu- 

 dents regard them as a highly specialized branch from the same 

 parent stock. The fact that the boring habit of the larvae is 

 apparently acquired lends color to this opinion, but I cannot 

 regard the small head as a necessary accompaniment of the bor- 

 ing habit. Rather than assume an elaborate process of evolution 

 for the reduction of such a specialization as the large head, I 

 regard the Megathymidae as a line separated from the parent 

 stock of the Pamphilinae before the increase in size of the head, 

 and proceeding by parallel development to a point of higher 

 specialization of similar structures. 



The three subfamilies of Hesperiidae are easily distinguished, 

 apparently natural groups. The only question regarding them 

 is that of relative position, and the present arrangement of the 

 Hesperiinae between the Pamphilinae and Papilionoidea is favor- 

 ed by most of the evidence, though in the structure of the imago 



