220 The University Science Bulletin. 



the eighth sterna. Laterally this pocket is bounded by the continu- 

 ation of the dorsal membrane to the seventh and eighth pleura. The 

 anterior portions of these lateral membranes are strongly chitinized 

 and curve mesad ventrally. 



The terminal segments of the female abdomen bear the external 

 organs of reproduction and are modified for this purpose. Segment 

 eight i^ represented externally only by the tergum and the pleura. 

 The tergum is essentially the same as in the preceding segments, 

 but narrows slightly caudad. The pleura narrow caudad and are 

 triangular in shape. They include the ventral cephalic portion of 

 the ninth segment between them and bear the last pair of spiracles. 

 Externally segment nine consists only of a tergum, commonly called 

 the pygofer, which almost completely encircles the abdomen, leav- 

 ing only a ventral groove in w'hich the ovipositor is folded. Ven- 

 trally it extends cephalad, ending in two obtuse points between the 

 eighth pleurites. Tlie caudal portion encircles nearly the whole seg- 

 ment and tapers towards its caudal end. 



The anal tube is composed of segments ten and eleven. Segment 

 ten arises from the narrowed apex of segment nine and is short and 

 tubular. It connects by a distinct intersegmental membrane with 

 segment eleven, which is also tubular and can be telescoped within 

 segment ten. Segment eleven bears the telson, the extreme apical 

 portion of the abdomen. Along the dorsal edge of the telson is the 

 anus, an opening running for its entire length and guarded by hairs. 



There are eight spiracles in the abdomen of the female located in 

 the first eight segments as described. 



Along the ventral side of the abdomen there occur many short, 

 fine hairs, which in all cases point backward. The hairs on the ninth 

 segment, or pygofer, are somewhat longer than those on the other 

 parts of the abdomen. 



THE OVIPOSITOR. 



(PL XXI, figs. 4-9.) 



This description was made from the ovipositor of Oncometopia 

 lateralis (Fabricius). However, in the many other species of leaf 

 hoppers examined, the fundamental structure of the ovipositor was 

 lound to be the same as for the species here described. 



The ovipositor of the leaf hopper is fitted for sawing slits in plant 

 tissues and for placing eggs within these slits. When not in use it 

 lies in the groove in the ventral surface of the ninth segment. The 

 ovipositor consists of three pairs of valves or gonapophyses. The 



