NO. 13 STAPH YLINIDAE — BLACKWELDER 81 



braiious plate chitinized along the edges. On the ventral aspect at the meeting 

 of the lobes there is a small trident body attached to a rod which lies free 



within the segment The anus opens on a membrane between the lobes ; 



the rectum can be protruded. 



Since Muir's figures of H. capillaricornis agree essentially with the 

 structure of H. schzvard, a discussion of his interpretation in the light 

 of the present material seems to be justified. The large pleural plates 

 are in the present species membranous except for a framework of 

 sclerotic rods or struts. The spiracles lie on the dorsal aspect of these 

 and identify them as paratergites. The transverse piece behind these 

 and articulating with them probably does represent the tergite, but 

 it is completely fused with the ventral plate by means of the sclero- 

 tized bars. The trident body appears in this species to be distinct from 

 the ninth segment, and the lateral parts seem to articulate with the 

 middle one and with the end of the supporting rod. The membranes 

 forming the aedeagus are practically invisible in this specimen. 



THE GENITALIA 



The male genital tube in this family is characterized by the high 

 state of specialization, by the modification of the median lobe for the 

 evagination of the internal sac by blood pressure, and by the absence 

 of a basal piece. Some of the most extreme modifications occur in 

 the lateral lobes, which are always present and usually separate. 



The most frequent type of genitalia is that represented in figures 

 9 G and 28 J, K. It consists of a strong sclerotic tube with a bul- 

 bous base, and a median foramen small and situated ventrally at the 

 junction of the tube and bulb and between the base of the lateral lobes. 

 The lateral lobes may be united into a plate basally but form two 

 narrow lobes which usually lie along the median lobe. This type has 

 been found in the following species : Geodromicus, Pelecotnalhim, 

 Lathrimaeum, Eumalns, Trigonurus, Phloeocharis (fig. 28 J), Crco- 

 philus (fig. 9 G) , Staphylinus, Ocypns, PhUonthus (fig. 28 K) , Cafitts, 

 Hadrofes, AcylopJwrus, and Quedius. It seems to characterize the 

 subfamily Staphylininae except for the tribe Xantholinini. 



The Xantholinini are said by Sharp and Muir (1912) to be " one 

 of the most highly specialized forms of Coleoptera." The two species 

 studied do not show the complicated structure of the tip of the aedeagus 

 of Sharp and Muir's species but are rather simpler than many others. 

 In Xantholinus (fig. 28 F), according to Sharp and Muir (1912) : 



.... the bulbous median lobe is of an extreme form, being egg-shape, with a 

 small membranous distal portion to which the greatly reduced lateral lobes are 

 attached. The median lobe is formed of dorsal and ventral sclerites, round, and 



