38 The University Science Bulletin. 



this sex there showing externally but six sternites, those of the 

 second to seventh segments, inclusive. In the male the ninth tergite 

 is not as large, for in this sex the sternites of segments two to nine, 

 inclusive, all show clearly. This tergite bears, however, on either 

 side, a pair of broad lobes or plates which Funkhouser calls the 

 lateral valves. These, he thinks, may be the pleura of the ninth 

 segment and of use in copulation. They may project caudad or 

 turn mesad — a character of generic value. They frequently bear 

 variously shaped processes or teeth, which, as far as the writer has 

 observed, are constant in form and position for the various species, 

 and are therefore good specific characters. 



The sternite of the seventh segment of the female differs in differ- 

 ent species, and is therefore of systematic value, as is also the 

 ninth sternite or sternal plate of the male. The latter is constant 

 in shape and extent of apical splitting within the species, and this 

 makes it of value as a taxonomic character. 



THE MALE GENITALIA. 



As in the Cicadellidae, the abdomen of the male ends in what 

 Sharp calls the "terminal chamber" in the case of the Pentatomidse. 

 This chamber is bounded above by the anal tube and ninth tergite, 

 laterally by the lateral valves, and ventrally by the ninth sternum. 

 Within this chamber are found the genital organs of the male, their 

 position and structure being exactly homologous with the male 

 genitalia of the leaf hoppers. 



The styles or claspers are always paired, both members of the pair 

 being alike, and fastened to the sternal plate by apparently passing, 

 near their middle, through the membrane forming the dorsal surface 

 of the plate. The cephalic portion of the clasper projects into the 

 abdominal cavity, frequently reaching the sixth segment, though 

 usually extending only as far as the eighth or ninth. It does not 

 seem to vary much in the different species. The apical portion, 

 however, is characteristic in its shape and apical structure, some- 

 times being nearly straight, at other times more or less strongly 

 curved, and ending either in a plain acute point or in variously 

 shaped and toothed extremities. So far the writer has found no two 

 species in w'hich the styles are alike in both size and structure. 



Canon Fowler, in the "Biologia Centrali-Americana," states that 

 in the genus Ceresa the styles are long and pointed, while in the 

 genus Stictocephala they are short and obtuse at the apex. This 

 is undoubtedly frequently true, but the writer has found that it does 



