The Pselaphid^ of North America. 229 



eighth, tenth obconical, truncate at base, twice as wide as long, 

 eleventh ovate, base truncate, wider than the tenth and a Httle 

 wider than long. Prothorax equal in length to the width of 

 the head with the eyes included, a little wider in the middle 

 for about one-sixth of the length. At this point the sides 

 are strongly arcuate, anteriorly and posteriorly becoming 

 nearly straight, neck half as wide as the base. Disk coarsely 

 and deeply punctured with two slightly marked circular 

 impressions one-sixth of the distance from the neck, and a 

 deeper fovea on each side near the base connected with its 

 fellow by a straight conspicuous sulcus. Basal margin just 

 perceptibly raised in a sharp ridge. Elytra coarsely punc- 

 tured, rather depressed anteriorly, the width across the 

 shoulders equal to the length of the suture, and one-eighth 

 more than that of the prothorax. They are widest one-fourth 

 of the length from the tip and here the width is one-third 

 greater than at the shoulders, which are prominent as a 

 rounded, elevated ridge. Disk not very convex, sutural lines 

 straight, nearly parallel, suture depressed, discal lines rather 

 sulciform at base, evanescent near the middle. Abdomen 

 very broadly margined, first dorsal as wide as the elytra, 

 widening behind, length, one-fourth of the width, and with 

 two entire longitudinal carinee including about one - half 

 of the segmental surface; posterior segments very convex, 

 the margins converging. Ventral segments equal, the last, 

 in the male with a small digital impression. Legs strong, 

 anterior femora strongly tri-spinous.. Tarsi half as long as 

 the tibite the second joint just visibly longer than the third. 

 Claws equally strong. 



Habitat. East and west of the Alleghenies, along the Ohio 

 river to Missouri and Southern Iowa. 



C. SPiNOSus, Lee. Umber brown, punctate, pubescence 

 short, appressed. Length, 1.9 mm. Plate ^T., Fig. 10. 



Head broader than long, tempora as long as the eye, which 

 has coarse facets. Frontal tubercles more than twice as wide 

 as long, separated by an ample sulcus, which is faintly pro- 



