DOERINU: I.Kl'VHOMA QIADRANGULARIS. 547 



chirinous i-od at a point wIum-c the caudal oorn(M's of postgense are 

 joined to tlie mandibular sclerite. Tiie maxilla is fastened to the 

 anterior rorncr of the maxillary sclerite, which places it cephalad 

 of the mandible. Funkhouser (1917) states that in the Membracidse 

 they are attached to the vertex, which differs from the condition 

 found in most other insects, where they are attached to the post- 

 genae. In Lcpyronia quadrangulari.s neither of these conditions 

 occurs, but the close approximation of the mandibular sclerite to the 

 postgena may be significant. 



In order to study the structure of the tips of the mandible and 

 maxilla it was necessary to study them under high magnification. 

 Both stylets are cylindrical in shape, tapering toward a blunt point 

 and with their hidden bases broadening into flat plates. The outer 

 margin of the distal third of the mandible is finely notched, w^iile 

 the outer apical part only of the maxilla is modified into five dis- 

 tinct, rounded teeth (pi. LVI, fig. 4). The maxilla? appear to be 

 equal to the labium in length, but the mandibles are slightly longer, 

 so that their tips protrude a short distance beyond the tip of the 

 labium. 



The four stylets are closely associated, converging at the place 

 where the labium is attached to the head. Here the mandibles be- 

 come joined together by their inner margins, forming a shallow 

 sheath in which the maxillae lie. The maxillae are also united, prob- 

 ably forming a tube, as in the Cicada (Snodgrass, 1921), through 

 which the sap is sucked up into the pharynx. The maxillae of 

 Lepyronia, however, do not appear to be so firmly joined as in the 

 Cicada, for their tips often spread apart, until from a superficial 

 view, they appear to be on the outside of the mandibles. 



The maxillary sclerites (pi. LVI, fig. 2) are the large semicircular 

 sclerites on the ventral aspect of the head, bounded laterad by the 

 genae, caudad by the mandibular sclerites, and mesad by the clypeus 

 and labrum. The cephalic tip' of each maxillary sclerite is con- 

 nected to the maxilla by a slender, chitinized branch of the latter. 

 These sclerites are homologous to the lorae of the Cicadellidae. Snod- 

 grass (1921) considers them as definite sclerites, but attaches no 

 name to them. 



The mandibular sclerite (pi. LVI, figs. 1, 2) extends from the 

 caudal angle of the genae and postgenae to the base of the labium. 

 Each sclerite is elongate, narrow at the base, but widening in the 

 middle to a flangelike projection and tapering to a tonguelike apex 

 which partially folds around the base of the stylets. The interior 



