PYGOFER OF THE TETTIGID^. 157 



Dr. Sharp, belonging to the Hemiptera-Heteroptera, 

 may be traced in a modified form amongst the Tetti- 

 gidas : particularly this is so in the genera Delphax, 

 Lihurnia, Deltocephalus, and Typhlocijha. With due 

 acknowledgment to Dr. D. Sharp I purpose to use such 

 of his observations as seem to bear upon the genitalia 

 of our British Cicadas. 



On Plate LXXV. a sketch will be found which has 

 been constructed as an average from the details of 

 other of my plates. It is strictly diagrammatic, and 

 it is chiefly useful as putting into some kind of order 

 anatomical parts, which may appear sometimes in one 

 species, sometimes in another, or perhaps in cases where 

 several details may appear collected in one individual. 



Dr. Sharp speaks of the "rectal cauda " of the 

 Pentatomidse, and he thinks that it forms the termina- 

 tion of the alimentary canal. This appears to me 

 highly probable. I have shown, elsewhere, that the 

 Cauda is a pretty constant appendage to the terminal 

 segment of the Aphides, and it is almost always repre- 

 sented, in some form or other, in the Homoptera 

 described in this Monograph. 



Amongst other examples, the drawings given on 

 Plate XLYI. fig. 4, Plate LIL, figs. Sa and 36, Plate 

 LXXI., fig. 4:h, seem to justify the above conclusion. 

 The Cauda is obvious in Athysanus, Deltocephalus, and 

 Ttjphlocijba. The cauda is common to both male and 

 female insects, and in many instances the alimentary 

 tube in both sexes can be traced to its orifice at the 

 apex of the organ. 



The rectal cauda in the Pentatomidse is believed 

 also to act as an operculum or protective cover to the 

 cedeagus, but in the Jassidse its form and small size 

 can hardly admit of such an adaptation. The com- 

 plicated structure called the oedeagus is placed below 

 the cauda, and is of much importance, since it con- 

 tains the intromittent organ which in the Tettigidge is 

 very delicate, and sometimes accompanied with fine 

 and long setae. In Heteroptera the oedeagus is 



