102 JOURNAL OF ENTOMOLOGY AND ZOOLOGY 



CiTHERONIA REGALIS 



This form (Figs. 6 and 8) shows a decided, transverse projec- 

 tion on the clypeus, probably about the place where it is joined to 

 the labrum, although the clypeo-labral suture is indistinct. The in- 

 vaginations for the anterior arms of the tentorium are small and 

 located at either end of the transverse ridge. The labrum (Fig. 

 6, lb) is slightly convex at the proximal margin, concave at the 

 distal margin and its width is less than twice the length. The 

 mandibles could not be clearly distinguished in the specimen at hand, 

 but as it had emerged from the pupal skin they were doubtless so 

 fused with the genae as to be indistinguishable. The maxillae (Fig. 

 6, mx) are not as long as the head and are slender with each half 

 the maxillae tube-like, tapering to a point at the distal end, where 

 they are strongly recurved. The labial palpi (Fig. 6, Ip) are large 

 and prominent, two-segmented, the distal segment porrect, and the 

 whole appendage densely covered with setae. 



Dryocampa rubicunda 



In this form (Figs. 7, 11 and 13) there is a distinct suture be- 

 tween the clypeus (Fig. 13, cl) and labrum (Fig. 13, lb), with the 

 invaginations for the anterior arms of the tentorium located at each 

 end. The portion of the clypeus adjoining the labrum is elevated 

 into a prominent transverse ridge similar to that in Citheronia 

 regalis. The labrum is convex along its proximal margin, concave 

 on its distal margin, considerably elevated above the surface of the 

 clypeus and much wider than long. Laterad of the labrum are 

 structures which have every appearance of being functionless man- 

 dibles (Fig. 13, md). They have a distinct suture at the proximal 

 end and are quite heavily chitinized along the distal margin, but 

 not toothed. The maxillae (Fig. 13, mx) are very small and lie 

 adjacent on the meson, the distal ends pointed and projecting slightly 

 cephalad. The labial palpi (Fig. 13, Ip) are slightly longer than 

 each half of the maxillae, clavate, and covered with long setae, more 

 numerous on the lateral margin. 



