8o SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 94 



it is more convenient to restrict the discussion of the " genitaha " 

 to the consideration of the genital tube or aedeagu's alone. For this 

 reason the eighth and ninth segments of the males will be discussed 

 briefly here. 



The posterior border of the eighth segment is frequently modified 

 in the male. This modification may take the form of lobation, emar- 

 gination or incisure, abnormal vestiture or sculpture, etc. It is gen- 

 erally the last visible segment of the abdomen, though it may be so 

 far retracted v^^ithin the preceding segments as to be invisible. 



The ninth segment is represented by a tergite, a sternite, and tv^o 

 small lateral plates bearing the valvulae or gonapophyses. The gona- 

 pophyses are present only in the subfamily Staphylininae excepting 

 the Xantholinini. In the other species studied the lateral plates (mor- 

 phologically the bases of the segmental appendages) are present, gen- 

 erally large, and frequently appear much like gonapophyses but w^ith- 

 out any sign of basal articulation. In some species these two plates are 

 joined by a narrow or wide bridge on either the dorsal or the ventral 

 aspect. The species in which these lateral plates are thus united in- 

 clude Gcodromicus, Pelecomalium, Tanyrhinus, Lathrhnaciim, Steniis, 

 Gastrolohium, Hesperohiwm, Lathrotropis, Stiliciis, Trachysectus, 

 Hypocyptus, Tachyporus (fig. 28 D), and Bolitohius. The species 

 examined in which these sclerites are not united include Trigonurus, 

 Phlococharis, Blcdius, Oxytelns, Metoponcus, Xantholinus, Xenodusa, 

 Lorinota, Alcochara, and Baryodma. The greatest amount of union 

 was found in Bolitohius in which the long sclerite formed is obvi- 

 ously dorsal. On the other hand in Tachyporus the union is said by 

 Muir (1920) to be ventral, and the present observations confirm this. 



A very much more remarkable modification than any other is found 

 in the eighth and ninth segments of Habrocerus (fig. 28 E). The 

 spiracles of the eighth segment are the most important landmarks and 

 are situated on the dorsal aspect (sp. 8). According to the inter- 

 pretation of Muir (1920), which differs somewhat from that of 

 Weber (1911) : 



.... the eighth segment is highly modified and consists of four pieces. A 

 large pair of pleural plates, on which the eighth spiracles are situated, embrace 

 the lateral area, and from the apex of each a large, spine-like style arises ; the 

 dorsal aspect consists of a very short tergite, and the sternite consists of a 



large plate more heavily chitinized round the edges The lateral portion 



of the eighth tergite articulates with the lateral edges of the sternite and also 

 articulates in a depression at the base of the pleural plates. . . . The ninth seg- 

 ment is highly modified and shaped like an oat. The distal and visible portion 

 consists of a pair of pointed and slightly curved lobes connected in a V-shaped 

 piece on the dorsal aspect ; the basal and internal portions consist of a mem- 



