86 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 89 



sented only by the membranous bridge between the bases of the first 

 valvifers and the first valvulae anterior to the opening of the genital 

 chamber (C, D, VI I IV). 



The first valvula is a thick lobe (fig. 27 D, E, iVl) about two thirds 

 the length of the first valvifer. In its outer surface is a plate provided 

 distally with short spines. The proximal ventral angle of the plate is 

 prolonged as the outer ramus of the valvula (E, rivlo), and is 

 attached to the lower basal angle of the first valvifer (B, C, iVlf), 

 thus leaving no doubt of the identity of the latter. The dorsal proximal 

 angle of the first valvula forms the inner ramus (E, rivli), which is 

 attached, in the manner characteristic of Hemiptera, to a process (w) 

 from the ninth tergum (IXT). The dorsal surface of the first valvula 

 contains two parallel sclerotic ridges, between which is a groove into 

 which fits a ridge on the ventral surface of the corresponding second 

 valvula. 



The second valvifer is an oblong plate (fig. 27 E, 2Vlf) lying mesad 

 of the ventral arm {n) of the ninth tergum, and articulated to the 

 ninth tergum at a point {p) near the middle of its dorsal margin. 

 Its distal end has a free, truncate edge, representatives of the third 

 valvulae being absent in Anasa, though these lobes are usually present 

 in other Hemiptera (fig. 26 E, 3VI). 



The second valvulae are united with each other, except at their 

 distal ends, which form two short free lobes (fig. 27 D, 2VI). The 

 basal part of each has a broad membranous connection with the cor- 

 responding second valvifer (E), and the ventral surface bears a strong 

 median sclerotic ridge that slides in the groove of the first valvula. 



The mechanism of this ovipositor is evidently such as to cause 

 alternate back-and- forth movements of the upper and lower valvulae 

 on each other. The movable articulations of the second valvifers on 

 the ninth tergum (fig. 27 E, />), and the firm union of the first val- 

 vulae with the ventral arms {n) of the tergum assure an opposite 

 movement in the two pairs of valvulae. The muscles arising on the 

 ninth tergum and inserted on opposite ends of the second valvifers 

 rock the latter up and down and thus move the attached dorsal val- 

 vulae ; but the same muscles pulling on the tergum impart an op- 

 posite movement to the ventral valvulae through the leverlike arms 

 {11) supporting the latter. 



AMBLYDISCA GIGAS FOWLER 



The ovipositor is well developed in the Cicadellidae, and the family 

 is one of considerable economic importance, but since most of the 

 species are very small it is a difficult matter to make a satisfactory 



