Anatomy of the Male Genital Title in Coleoptera. 485 



Insecta that most nearly approximates to the Verte- 

 brate penis is the internal sac, the knowledge of 

 which has been almost nothing until its recent in- 

 auguration by Jeannel. The median lobe appears to 

 be sometimes a complex or amalgamation of more or 

 less individualised sclerites. (Cf. HydropMlus.) 

 Lateral lobes. Though a very suitable term for the 

 parts in the various trilobe forms, it is inappropriate 

 in cases where the projections (if homologous at all) 

 are medianly situate. Paramere is quite as good as 

 lateral lobes. Cornua (meaning cornua tegminis) is 

 also not free from objection, and accessory process 

 is rather cumbersome. Tegrainal lobes might do if 

 the term tegmen be itself accepted. 

 Basal-piece. Perhaps this term may stand till more is 

 known about the cases in which it is two pieces, and 

 those in which it appears to be absent. 

 Internal sac. Probably the term Vesica might be prefer- 

 able. But this part of the conduit is so protean in 

 form and development that it might be better to 

 invent a term indicating a structure that is pre- 

 dominantly membranous. 

 Tegmen. This term seems convenient and adequate for 

 the layer of sclerites external to the median lobe. 

 The elytra of grasshoppers are frequently called 

 tegmina, but we do not think this objection to our 

 use of the term a serious one. 

 Connecting membranes. This term cannot be com- 

 mended. It gives the idea that the sclerites are the 

 important structures. But the tube may exist without 

 sclerites and is it then a connecting membrane ? 



Other terms (such as Prepuce) that have been used for 

 various parts are totally unsuitable. We consider that it 

 is premature to endeavour to establish permanent terms 

 for the parts of the complex genitalia of Insects till the 

 various Orders have been more thoroughly examined and 

 compared. 



