306 W. D. FUNKHOUSER 



In tte Membracidae two ocelli only are present. It would appear, there- 

 fore, that in this family the frons has disappeared, and with it the median 

 ocellus which it contains. If, then, the triocellar condition is the more 

 primitive form, the Membracidae in this respect are rather highly 

 specialized. 



The labru7n is a single, heavily chitinized, subcylindrical piece attached 

 to the distal end of the clypeus and projecting usually ventro-caudad 

 from that sclerite (Plate xxxij 1-4). Because of the inclined or prone 

 position of the head, this piece is not visible except occasionally at its 

 basal part from a strictly cephalic view of the insect (Plate xxxii, 1). Little 

 variation is noticed in the labrum, but in the subfamily Hoplophorinae 

 it tends to be shorter and stouter than in other membracids. Altho in 

 the Membracidae the labrum should perhaps be considered as one of the 

 head segments, not as an appendage (Comstock and Kochi, 1902:16), 

 it is more or less movable in life and probably serves to support and 

 guide the rostrum. 



At the extremity of the labrmn arises a small triangular piece, the 

 epipharynx (Plate xxxi, 2). This sclerite is always distinct in both 

 nymph and adult. In the former it appears as a soft, light-colored, fleshy 

 extension of the labrum; in the latter as a stiff, hard, sharp segment 

 distinctly set off at its base. In position it follows the general course of 

 the labrum. 



The genae form the lateral outline of the head and give the facial con- 

 tour which is sometimes used in systematic diagnosis. Each gena is 

 irregular in shape, being bounded dorsad by the vertex and mesad by the 

 clypeus. Its lower extremity is contiguous with the base of the labrum. 

 In general outline it is usually a long, rather flat plate, beginning at the 

 lower margin of the eye and continuing to the rostrum. In the Smiliinae 

 the ends are more or less pointed and the middle is swollen; in the Mem- 

 bracinae the entire sclerite is inclined to be nearly quadrangular. The 

 genae are not set in the same plane as the frontal surface, but extend 

 slightly caudad, so that the width of the sclerites determines in part 

 the depth of the head. 



Just behind the genae and forming the basal surface of the epicranium 

 are the postgenae. These sclerites extend from the occiput to the labrum 

 (Plate xxxi, 1, 2) and are most irregular in shape. The upper extremity 



