604 Mr. D. Sharp and Mr. F. Muir on the Com^Jarative 



must admit that the term is not a good one. The part in 

 question is highly complex. It is in fact the layer, or 

 layers, of the tube of which sclerites of the aedeagus form 

 a large, or the larger, part. 



The sclerites on the phallic portion of the genital tube 

 form two groups. (1) Those situate on the distal portion 

 of the tube (furthest from the body wall), which we call 

 the median lobe (fig. 239, 5-4), and (2) those situate 

 nearer the base, which we call the tegmen (3-2). The 

 membrane between these two groups of sclerites we term 

 the first connecting membrane (4—3), and the membrane 

 at the base, joining on to the body wall, we term the 

 second connecting membrane (2—1). The median lobe, 

 together with the tegmen, we term the aedeagus. 



The point Avhere the genital tube is reversed (5-d) we 

 call the median orifice, and the lumen at the base of the 

 median lobe (4-to corresponding spot below) we call the 

 median foramen. Similar terms could be applied to the 

 tegmen, but we have not found them necessary for our 

 descriptions. 



Having thus given a description of the four parts of 

 the tube, we now give remarks as to the structures of each 

 of the four divisions. 



The second connecting membrane (or prephallic portion 

 of the tube) varies in extent according to the size and 

 shape of the aedeagus. In certain cases (i. e. Laccohius and 

 Sphe7iop1iorus) it is chitinised in part, and forms a covering 

 round the aedeagus. At, or near, the base there is in 

 many forms a chitinous rod with one or two prongs at the 

 end, embedded in the membrane. This is the "Stengel" 

 of Lindcmann, " Rod " or "fork " of Hopkins, and " Spiculum 

 gastrale " of Verhoeff. Hopkins considers it as represent- 

 ing the ninth steruite. A comparison of this in the various 

 families would be of great interest, but would entail a 

 study of the body segments, a task beyond the scope of 

 this memoir. We have therefore left it out of consideration. 



The phallic portion of the tube is the one that has 

 chiefly attracted the attention of coleopterists. It consists 

 partly of membrane, partly of sclerites, and there may be 

 most extreme differences in the chitinisation of its different 

 parts, excessively hard chitin being continuous with dehcate 

 membrane. We have already explained that we call the 

 sclerites in question the aedeagus, and that this consists of 

 two parts, viz. median lobe and tegmen. 



