41G Dr. David Sharp on the structure oftlie 



group, not otherwise mentioned in this paper, the 

 structure and position of the terminal chamber is quite 

 different from anything I have described ; so that 

 evidently in this group very extraordinary modifications 

 are to be found. 



The anterior chamber I shall not further allude to, as 

 the parts with which I am now concerned are situated 

 in the posterior chamber. Passing to this part : it will 

 be seen that its posterior margin is to a greater or less 

 extent unoccupied ; this part may be conveniently called 

 the lip, this term including the space between the inferior 

 process and the hind margin of the segment. The lip 

 varies extremely in its form ; it may be prolonged in the 

 middle, the prolongation differing in size and shape 

 according to the species, or it may, on the contrary, be 

 deeply divided along the middle, being thus more or less 

 completely cleft into two halves. Cantao ocellata is an 

 example of a species with the lip prolonged in the middle, 

 while Dalpada oculata is one in which it is deeply 

 divided. 



In the species of Tcsseratoma the lip bears in the 

 middle a large raised process extending forwards towards 

 the inferior process. I have not observed a similar pro- 

 cess in any other genus. 



The diaph ragm . — This is the part that limits the posterior 

 chamber in front, where it appears as a deflection of the 

 upper surface on each side of and around the cauda ; it 

 differs greatly in its direction, in some descending per- 

 pendicularly, in others remaining nearly horizontal : it 

 also differs greatly in texture, colour, and sculpture, and 

 in the clothing it bears. It appears in its most remark- 

 able condition in Chrysocoris ornatus, where it is very 

 abruptly inflexed, pallid in colour, and large in extent, 

 and ornamented with patches of black scales or asperi- 

 ties. 



The rectal-cauda. — The rectal-cauda, or the cauda, as 

 it may for the sake of brevity be better called, is the 

 most remarkable of the external male characters in the 

 Pentatomidce. It differs, however, greatly in the different 

 species and genera. It is comparatively insignificant in 

 Poecilochroma lata, but becomes a truly extraordinary 

 process in Edessa, in Nezara, and in Catacanthus. In the 

 larger Tesseratomincs, — genera Tcsseratoma, Eusthenes, 

 and Eurostus, — it is horizontal in its direction, and 



