Anaiomy of the Male Genital Tube in Coleoptcra. 505 



ring-like basal-piece, broader on dorsal than on ventral aspect, with 

 a pair of narrow, pointed lateral lobes pressed close to the sides of 

 the median lobe. The internal sac not large, but with complex 

 armature at apex (53a, 53&). A flat, curved median chitin-piece (b) 

 is attached to the internal sac by a large chitin knob (c) through 

 which the ejaculatory duct runs and opens on the end of the median 

 piece ; a chitin plate (d) with a second chitin knob (e) gives it greater 

 support. To each side of the chitin knob (c) is attached a flattened 

 pointed process, thickened at its base at the point of attachment, one 

 is slightly longer than the other. 



Clamhus mimitus (PI. L fig. 54). 



Median lobe a thin, partly flattened, tube, with the dorsal distal 

 part drawn out into a curved process hooked at the tip, the ventral 

 distal part into a semi-membranous tongue. The lateral lobes are 

 amalgamated for two-thirds of their length and form a broad shallow 

 plate with the distal third forming unequal points, bearing a couple 

 of stout spines. The basal-piece ring-shape (bp). Internal sac not 

 examined. 



Among the Silphidae s. 1. that we have examined there 

 are three distinct types of aedeagus. The first is repre- 

 sented by Silpha, in which the median foramen is small, 

 the median lobe collapsible on the dorsal aspect and forms 

 a collapsible bulb by means of which the internal sac is 

 evaginated by fluid-pressure, and the sac bears no chitin ous 

 armature. In the second the median foramen is large, 

 and the median lobe is not collapsible and does not function 

 as a bulb for the evagination of the sac, and the sac bears 

 chitinous armatures. 



The third type has the lateral lobes amalgamated to- 

 gether to form one piece, and the median lobe is tubular 

 and not collapsible. 



These characters do not quite agree with the divisions 

 into families of the Silphid allies. As, however, the recent 

 authorities are not in accord on this point, and as we have 

 studied a very small percentage of the known forms, we 

 have treated the assemblage as one family. But we hope 

 our doing this will not be interpreted as supporting either 

 one view or the other. 



The Silphid type approaches the Staphylinid type, but 

 the presence of a reduced basal-piece serves to distinguish 

 the two. 



