MALE ORGANS OP GENERATION. 2 1 I 



into the penis. In the other Capricorn beetles (for example, Cullichroma 

 moschatum,} the ductus ejaculatorius is indeed much shorter, but like- 

 wise twice geniculated. That portion from the point of connection to 

 the first knee is wider, more vesicular, and transversely ridged, taking 

 the place of the sperm bladder, which is wanting, to the equally wide 

 sperm ducts ; the other, double as long but much narrower portion, 

 bends forwards as far as the commencement of the sperm bladder, 

 re-bends back to the anus, and then passes into the penis, having 

 reached the spot of its first geniculation. The penis, or rather its 

 exterior case, is united to this first knee by means of a muscle. 



We are as yet unacquainted with other remarkable or peculiar forms. 



B. EXTERNAL ORGANS OF GENERATION. 

 152. 



THE PENIS. 



Having already perceived a great variety of form in the female 

 external organs of generation, we might expect to find this still more 

 extensively the case in the male organs, had their parts been as widely 

 investigated and described. But that which does not invite close 

 inspection by its exterior or the problematical nature of its form, but 

 much rather withdraws itself from the eye of the inquirer, and is con- 

 cealed upon a first superficial examination, does not so easily excite 

 curiosity and stimulate the desire for instruction, because it is not sup- 

 posed to exist. This is the reason why the structure of the penis has 

 been made less frequently the subject of description than the female 

 ovipositor, although possibly there is no other so variously formed 

 an organ, nor one subjected to such characteristic and generic dif- 

 ferences. 



The PENIS of beetles consists essentially of two parts, namely, of the 

 exterior horny case analogous to the bone in the penis of the dog, and the 

 internal delicate membranous penis itself, which admits of being consi- 

 dered the free ductus ejaculatorius. The exterior sheath alone is visible 

 upon a first examination, as it entirely covers the internal tube and allows 

 it only at its apex, where it is divided a little, to project. This sheath is 

 clothed, either entirely or partially, by a delicate membrane (the prae- 

 putium), which may be considered as a continuation of the inner mem- 

 brane forming the cloaca. This membrane has also sometimes horny 

 ridges to support it. Thus much upon the penis in general ; more will 



P 2 



