Biology of the Membracidae of the Cayuga Lake Basin 349 



to a small triangular sclerite on cither side of the ovipositor and does not 

 extend entirely across the abdomen. In most cases no sternum occurs 

 in this segment. The ninth abdominal segment consists only of the 

 tergum, but this sclerite is much enlarged and makes up the larger part of 

 the posterior end of the body. This segment is not represented by a 

 pleuron in any species dissected and no spiracle is present to suggest such 

 a structure. The sclerite bends around to form most of the body wall. 

 The free ventral edges do not meet, but the space between them is occupied 

 by the styles of the ovipositor. This segment is most inclined to show 

 pubescence and well-developed hairs, and is the most conspicuous part 

 of the female abdomen. The tenth and eleventh segments are more or 

 less vestigial and are usually hidden under the posterior projection of the 

 ninth. On dissection, however, they appear as very small tergal plates 

 with a weakly chitinized ventral ring (Plate xxxviii, 11, 12). In fresh 

 material the segments may be dissected out, in which case the tenth seg- 

 ment appears as a complete ring with the dorsal surface firm and the 

 remainder of the ring membranous (Plate xxxviii, 13). On boiling in 

 caustic potash the lateral and ventral parts of the segment sometimes 

 disappear, leaving only the dorsal plate. The eleventh segment appears 

 merely as a small triangular piece with membranous extensions. While 

 these last two segments are much reduced, they no doubt represent the 

 regular tenth and eleventh abdominal rings, and, as will l^e noted later, 

 are more easily recognized in the male. The same interpretation has been 

 made by Berlese (1909:263) for other Homoptera and seems entirely 

 logical. 



The ovipositor consists of three pairs of styles. The outer pair is the 

 longest and incloses the middle pair, which in turn surrounds the inner. 

 The outer styles (Plate xxxviii, 14, 15) are roughly forceps-shaped, narrowed 

 at the base, wide and flat at the center, and hollowed out on the inner 

 sm-face to form a spoon, or paddle, the excavated part containing the 

 middle styles. The edges are smooth and the tips pointed. The outer 

 styles project below and beyond the ninth abdominal segment and are 

 plainly visible from an external view of the insect. They are often densely 

 pubescent, but seldom punctate. They are tightly closed except during 

 oviposition and mating, and form a smooth, rounded, ventral surface for 

 the apical end of the abdomen. The middle styles (Plate xxxviii, 16, 17) 

 are slightly smaller, narrower, and shorter than the outer styles, and fit 



