Readio: OviPCSiTORs of Cicadellid.e. 221 



inner two pairs alone t'uiictioii in sawing slits and placing eggs, and 

 the outer pair act as guards within which the two inner pairs lie 

 when not in use. In this discussion the valves are numbered I, II 

 and 111, according to their attachment, the most cephalic in attach- 

 ment being numbered I. 



Valve I is the outer and more ventral of the two inner pairs of 

 \'alves. Its chief attachment is to the eighth sternum, which is 

 divided and appears as two subrectangular, heavily chitinized 

 sclerites, for the most part hidden in the pocket above the seventh 

 sternum. Near its base, a narrow, curved rod leaves its dorsal mar- 

 gin and attaches basally to a small, triangular sclerite on the dorsal 

 side of the cephalic end of the pygofer. This small triangular scle- 

 rite is possibly the ninth pleurite. Upon attempting to separate the 

 narrow, rodlike portion from the rest of the valve, a featherlike 

 structure, consisting of a middle portion formed by the continua- 

 tion of the attaching rod and membranous side plates, can be drawn 

 out. However, except basally, this featherlike structure is en- 

 tirely incorporated into the main part of the valve, both structurally 

 and functionally. The main part of the valve is relatively broad 

 basally, narrows slightly beyond the base, broadens again towards 

 the middle, and narrows to a sharp, apical point. A heavily chitin- 

 ized rod strengthens the ventral portion of this valve. The rod 

 is comparatively large basally, narrows in the middle portion, and 

 is absent in the apical third. Along the entire dorsal border and 

 along the ventral apical border are diagonal rows of scalelike proc- 

 esses. Along its mesal surface, just dorsad of the chitinized rod, is 

 a mushroom-shaped groove into which a complementary tongue on 

 the outer surface of valve II fits. This permits independent sliding 

 of the two valves, but not complete separation. Basally the ven- 

 tral edges of this vah-e turn mesad, and on the dorsal side of this in- 

 turned portion is a less heavily chitinized projection. This projec- 

 tion in the one valve bears a tongue, and in the other a groove, unit- 

 ing the two basally. For the greater part of their length, however, 

 they are independent. 



Valve II is the inner and the more dorsal of the two inner pairs 

 of valves. It is attached to tlie cephalic end of a small sclerite, 

 which is attached to the pygofer. This sclerite is ventral in posi- 

 tion and possibly represents the ninth sternite. This valve is narrow 

 and rodlike at the base, but for its greater length is broad and flat. 

 It also possesses a chitinized strengthening rod whicli extends nearly 

 to its apex. On the outer surface of the valve, just ventrad of the 

 rod, is a tongue which fits into the groove in valve I. The dorsal 



