PSELAPHIDAE. 81 



(jrioui> i- — Pselaphi. 



In this group the aiitoiina3 are approximate, and inserted under 

 a hirge frontal elevation, which is channelled. The abdomen is 

 strongly margined. 



Tarsi with ungui^s two, oqual ; 

 Antennae moniliforni ; 



Maxillary palpi very small. Atinus. 



Maxillary palpi with the last two joints very transverse and lanielli- 

 form- Ceophyllus. 



Antennae clavate ; last joints gradually larger ; 



Maxillary palpi with the third joint transverse, triangular ; tin; fourth 

 ■ larger, convex. Cedius. 



Maxillary palpi with lateral setiform appendages ; 



Last joint lunate; abdomen carinate. Tmesiphorus. 



Last joint transverse, similar to the penultimat«-. Ctenistes. 



Maxillary palpi with the last joint oval, with a small terminal seta. 



Tyrus. 

 Antenna? with the last joint large, rounded ; 



Maxillary palj^i with the third joint very small ; the fourth long, cylin- 

 drical. Cercocerus. 

 Tarsi with a single unguis ; maxillary palpi excessively long ; 



Maxillary palxn with the last joint club-sliaped. Pselaphus. 



Maxillary palpi with the last joint hatchet-shaped: 



Frontal protuberance narrow, antennae straight. Tychus. 



Frontal protuberance broader, antennae subgeniculate, 1st joint elon- 

 gate, 2d globose. Bythinus. 



The anterior trochanters and thighs are armed with acute spines 

 in Ceophylhis and Cedius. Bamotus was founded by Aube on a 

 species (H. humeralia) wliich cannot be considered as properly 

 separated from Tyrus ; it is widely distributed, and occurs in the 

 Atlantic and Pacific regions. The genera are all represented in 

 tiic Atlantic States; thus far only Ctenistes, Tyrus, and Tychus 

 have been found in California. 



Group II. — Bryaxes. 



The antennte are distant at base, and inserted at the sides of 

 the head. The palpi have not the extraordinary development 

 seen in the previous group, and the last joint is oval or fusifornj. 



