The Pselaphidve of North America. 51 



mental width; fourth dorsal not prolonged. The first and 

 second ventrals longer, the second half as long as the first. 5 

 anterior thighs strongly clavate, last ventral transversely im- 

 pressed, otherwise like the ?. 



Habitat. Cedar Rapids, la. One pair sifted from rotten 

 wood in September. 



T. ARCUATUS, Lcc. Ycllowish brown, highly polished, 

 impunctate; legs and antennas pale; pubesence inconspicuous. 

 Length 1.2 mm. 



Head slightly wider than long, tempora parallel, angles 

 rounded, eyes small; vertex impunctate, with two small pubes- 

 cent foveee between the eves, mutuallv twice as distant as 

 either from the eye; sulcus feeble, wider and somewhat deeper 

 behind the frontal ridge; supra-antennal tubercles obliquely 

 oblong crossed by a short impressed Hne; labrum emarginate 

 anteriorly, with a transverse row of setse. Antennce one-half 

 longer than the head, f unicle moniliform, ninth and tenth joints 

 gradually wider, transverse, eleventh as long as the four pre- 

 ceding together, one-half longer than wide, conical, acuminate. 

 The last joint of the maxillary palpi is fusiform, twice as long 

 as thick. Prothorax widest across the middle, as wide as the 

 head and imperceptibly longer, sides evenly and strongly 

 arcuate anteriorly, and very slightly sinuate toward the base; 

 the neck is nearly as wide as the base; disk very convex, 

 basal fovcce one-fourth from the base, nude, the middle one 

 punctiform, the lateral ones large, connected by an arcuate 

 line. Elytra slightly wider across the shoulders than the 

 pronotum, length one-third greater than the width of the 

 shoulders; sides strongly arcuate; disk convex, sutural hnes 

 arcuate, discal lines deep, one-third of the elytral length. 

 Abdomen convex, wider across the third segment than at the 

 base, the first segment longer; no carinas. -Legs long, tarsi 

 slender, the second joint twice as long as the last. The under 

 surface of the head, behind the mentum, is hairy, each hair 

 ending in a small globule. The metasternum has a deep 

 fovea near the middle. 6, intermediate femora thicker. 



Habitat. Middle and Southern States. 



