NO. 13 STAPH YLINIDAE — BLACK WELDER 'J'J 



chanter but not extended laterally. It includes Micropeplus, the 

 Omaliinae, all the Oxytelinae except Osor'ms, Hypocyptus (fig. 26 H), 

 Tachyporiis, Tachinns, Erchomtis (fig. 26 D), Bolitohius, and all the 

 Aleocharinae except possibly Liparocephalus. These are chiefly the 

 forms said to have the coxae transverse. 



The third group contains only Habrocerus (fig. 26 K). The coxa 

 is rather triangular, but the upper surface is broadly expanded into 

 a lamella which covers part of the femur in repose and extends laterally 

 clear to the pleural articulation. 



Micropeplus appears to be distinct from all the others in the presence 

 of a narrow separate strip extending from the trochanteral articulation 

 to the pleural one. It may be a secondary separation from the coxa 

 but is entirely unique. 



THE ABDOMEN 



The abdomen of Staphylinidae is composed of 10 segments in all 

 the species studied. In all cases the first segment is represented only 

 by the tergite and rarely a paratergite on each side behind the spiracle 

 {^g.gA,ptt.i). 



The second segment may be entirely membranous, as is apparently 

 the case with Micropeplus. It may be represented by a tergite alone, 

 as in Trigonurus, Phloeocharis, Osorius, Stenus, Gastrolohium, Hes- 

 perobimn, Paederillus, Paederus, Lathrotropis, Hypocyptus, Liparo- 

 cephalus, Xenodusa, Lorinota, Aleochara, and Baryodma. A pair of 

 small paratergites is present at the sides in Geodromicus, Tanyrhimts, 

 Lathriiuacum, Pseudopsis, Creophilus (fig. 9 A) and all the Staphy- 

 linini, Glenus, Acylophorus, Quedius, Oxyporus, Habrocerus, Tachy- 

 porus, Tachinns, Erchomus, Bolitobius, and possibly Oligota. Be- 

 sides these sclerites the following also have some sclerotization of 

 the sternite : Pelccomalium, Proteinus, Eumalus, Xantholinus, and 

 possibly Metoponcus. The greatest development of this segment, how- 

 ever, is in the tribe Oxytelini. The species of this tribe have all the 

 sclerites completely developed so as to appear identical with the suc- 

 ceeding segments in structure. 



The third, fourth, fifth, sixth, and seventh segments are very 

 similar in structure. They each have a normal tergite and sternite 

 and usually one or two paratergites on each side. Only Leptochirus, 

 Eumalus, and Osorius are entirely without paratergites, and the 

 following have only one on each side : Micropeplus, all the Omaliinae 

 (fig. 27 D), Proteinus, Trigonurus, Phloeocharis, Pseudopsis, Stenus, 

 and Habrocerus. All the other species examined have two paratergites 



