The Pselaphid^ of North America. 2;^! 



angular, fourth triangular, free side emarginate, appendages 

 setiform, short. Body variolate. 



T. cosTALis, Lcc. Piceous, shining, pubescence short, ap- 

 pressed. Length, 3.3 mm. Plate VI., Fig. 13. 



Head, exclusive of the eyes, two-thirds as long as broad, 

 eyes very prominent, facets coarse. Frontal fissure deep, 

 branching behind the frontal tubercles toward the foveae, 

 which are situated on a line passing through the centers of 

 the eyes. Occiput convex; below and behind the eyes is 

 found a small, horizontal spine. Ajitciince of the male more 

 than one-half the length of the body, first joint cylindrical, as 

 long as the frontal margin and not quite half as thick; second, 

 one-third as long and two-thirds as wide as the first, cylin- 

 drical; third, fourth and lifth globular, as thick as the second '^ 

 sixth and seventh smaller, also globular; eighth, ninth and 

 tenth gradually larger, obconical, the eighth as thick as the 

 first, the tenth twice as thick; eleventh thicker and as long as 

 the ninth and tenth conjointly, emarginate on one side near 

 the base. Pubescence denser on the club. Female antennae 

 shorter, less robust, and without the basal emargination on the 

 last joint. Prothorax campanulate, widest at middle, as wide 

 and long as the head, convex, neck half as long as the base, 

 sides rounded at middle, straight towards the neck and base. 

 Disk with two slightly impressed foveje on the anterior fourth, 

 and an ample one on each side near the base; lateral margin 

 depressed, subsulcate by the convexity of the disk. Elytra 

 convex posteriorly, half as long again as the head, breadth at 

 the shoulders four-lifths the length of the suture, at the tip 

 one-third more than the shoulders. Humeri high, prominent, 

 discal lines in the form of a broad, flat-bottomed sulcus, abbre- 

 viated at middle, sutural lines parallel, curving outward at the 

 base. Abdomen broadly margined, first dorsal segment wider 

 posteriorly, this and the second carinate, the latter a little 

 longer. Ventrals subequal, flattened in the male, meta- 

 sternum longitudinally impressed in the middle. Legs very 

 long, slender, tibise slightly increasing in thickness toward the 



