158 BRITISH CICADA. 



embraced by the lips of a stout wall (theca). Two 

 lateral appendages often appear on each side of the 

 oedeagus, which seem to be homologous with the lateral 

 styles of the Tettigidse. 



In the last family these processes (styles) are mostly 

 hooked, whilst in other cases their apices are shaped 

 like a booted foot. 



It is not clear what function these organs fulfil. In 

 many species I believe they act as claspers, but pro- 

 bably they do more than this. In more than one 

 dissection they have appeared to me to be perforated ; 

 and if they be so, in addition to their action as holders, 

 they may pour some secretion into the vagina, Per- 

 haps also they act as wedges or expanders of the 

 passage through which the penis must pass. This 

 passage must be very intricate amidst the sheaths of 

 the saws and rasping blades, which function in the 

 female insect both as groove-cutters and as ovipositors. 



In some Heteroptera the male creeps below the 

 female whilst coupling ; but in the Homoptera the 

 male appears uppermost, the oedeagus being partly 

 protruded and curved downwards, in order to meet the 

 vulva. 



The inferior process is placed below, or else between 

 the lateral processes. Sometimes this organ is double, 

 or concave, or spoon-shaped. At other times it is 

 simple, and forms a sheath to the delicate penis, the 

 apex of which may be cleft into several laminae. 



Occasionally the penis is indicated by two, or else 

 three, long filiform organs, which 'may be the repre- 

 sentatives of the above laminae, most obviously seen 

 in the Typhlocybidae (see Plate XII., figs. 7 and 8). 



The reproductive parts of the male insect often 

 occupy the entire space of the terminal abdominal 

 segment. Possibly two segments are fused into one 

 for the elaboration of the pygofer, in which cases fewer 

 somites can be counted in the male than in the female. 

 These body-rino;s of the Tettigidae are sometimes 

 ornamented by fringes of hair, cottony tufts, or stria- 



