62 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 94 



extends distad almost or quite as far as the galea. These forms gen- 

 erally have both these structures less hairy and frequently armed 

 with spines. Of the species examined Gcodromiciis, Pelecomalium, 

 Leptochirus, Emnalus, Trigonurus, all the Oxytelini, Steninae, Paede- 

 rinae (fig. 17 D), Staphylininae (fig. 2G), Oxyporinae, Tachyporini, 

 and Bolitobiini have the lacinia much shorter than the galea, whereas 

 it is elongate in Micropeplus, Tanyrhinus, Lathrimaemn, Phloeocharis, 

 Pseudopsis, Osorhis (fig. 17 E), Habroccrns, Hypocyptus (fig. 17 C), 

 and all the Aleocharinae. 



The maxillary palpi are four-segmented in all the species except 

 Aleochara and Baryodina (fig. 17 G), in which there is a small ad- 

 ditional fifth segment. With the exception of Stenus (fig. 17 F), the 

 first segment is always small and geniculate. It is apparently im- 

 movably united to the second segment, at least in Thinopinus (fig. 

 17 A). Any of the succeeding segments may be much expanded, as 

 the second in Micropeplus (fig. 17 I), the third in Hypocyptus (fig. 

 17 C) and Paederus (fig. 17 K), or the fourth in Pinophilus (fig. 

 17 D). Occasionally the fourth is longer than any of the others, as 

 in Acylophorus (fig. 17 H) and Osorhis (fig. 17 E), but more fre- 

 quently it is greatly reduced, as in Gastrolobium (fig. 17 B), Hypo- 

 cyptus (fig. 17 C), and Stenus (fig. 17 F). In Paederus (fig. 17 K) 

 the terminal one is short, truncated, and strongly compressed. 



In nearly every labium studied the mentum and submentum are 

 the only heavily sclerotized parts. The submentum is continuous with 

 the gula between the tentorial pits and is generally separated at the 

 sides from the postgenae by the submental sutures. These sutures 

 may be complete from the base of the mentum to the tentorial pits, 

 they may be incomplete either anteriorly or posteriorly, they may be 

 united on the midline for a distance in front of the pits, or they may 

 be entirely lacking. They are complete in Lathrimaeum (fig. 12 H), 

 Stenus (fig. 12 G), Astenus (fig. 12 B), Hypocyptus (fig. 12 F), and 

 all others not listed in the three following categories. The anterior 

 ends of the sutures have disappeared to a varying extent in Pseudop- 

 sis, Trachysectus, Orus, Philonthus (fig. 12 J), Cafius, CreopJiilus, 

 Ocypus, Thinopinus, Hadrotes, GIciuis, Acylophorus, Quedius, Tachi- 

 nus, Tachyporus, and Erchonms. They are visible only at the anterior 

 end in Tanyrhinus (fig. 12 A). In Trigonurus, Bledius, Platystcthus, 

 Oxytclus, Aploderus (fig. 12 E), and Osorius they have become united 

 in front of the tentorial pits so that the submentum is a wholly dis- 

 tinct sclerite. The sutures are apparently entirely lacking in Micro- 

 peplus, Eunmlus (fig. 12 C), Metoponcus (fig. 12 I), and Oxyporus 

 (fig. 12 D). 



