The Graapedosomatidse of North America. 61 



posterior segments the bristles tend to separate from each other and to arrange 

 themselves in a transverse tow, the inside pair approach on the xjosterior seg- 

 ments very close to the median line. 



Anal segment short, posteriorly broadly tmncate-emarginate, vs'ith eight 

 bristles. The anterior two located near the median line and close to the an- 

 terior edge of the segment. Posterior six bristles much more slender than the 

 others, located along the posterior margin at about equal distances from each 

 other. The middle pair are not quite so close together as the others, and have 

 papilliform enlarged bases about one-fifth as long as the exceedingly fine flexi- 

 ble hair that proceeds from them. This segment, as well as a few ]oreceeding, 

 and the anal valves, is supplied with a scanty, short pubescence. 



Anal valves moderately convex, produced posteriorly into a rather sharp 

 point, considerably exceeding the last segment. Surface finely vertically stri- 

 ate-wrinkled. Margins not raised, the three bristles very slender, about 

 equally distant from each other and from the apex of the anal segment. 



Pre-anal scale small, semi-circular, with two very fine long bristles. 



Male genitalia (plate II, figs. 20, 21 ) simple, of a thin deeply bilobed lamina, 

 the lobes apically decurved and bidentate, the teeth long and connivent. The 

 anterior face is hispid at base with short hairs, which grade distad into papil- 

 lae; a few long variously curved hairs near the bottom of the fissure, and a few 

 others near the margin distad. On the posterior side (fig. 21) springing from 

 near the base of the lamina are two pairs] of plumose-laciniate processes, the 

 inner pair much shorter, and laciniate on both sides. 



Ninth legs of male two-jointed, the basal joint perpendicular, clavate, with 

 a few long bristles toward the apex, one of which is longer than the others and 

 curved basally. This joint passes insensibly into a membranous lamina 

 which connects the two joints and is not interrupted medianly. Second joint 

 oblong-oval, with a few bristles, near the upper and lower margins. On the 

 lateral face near the apex is a rounded chitinous knob, which may be inter- 

 preted as the rudiment of a claw. 



Color in alcohol, dull white. 



Length 9 mm. ; width .4 mm. 



We have had for study one male specimen collected by Dr. L. 

 M. Underwood at Luray Cave, Yirginia, September, 1887. 



The body of this species is nearly cylindrical, that is, less 

 fusiform than any other known to us. 



Owing probably to the cave life of this species, the exo-skele- 

 ton usually so hard and brittle, is soft and flexible. Pseudotremia 

 has not suffered so much modification, as the presence of eyes 

 also testifies. There appears to be very little carbonate of 

 lime present, so that on drying the skin of an alcoholic specimen 

 shrivels up like that of a spider. The legs and other parts vprinkle 

 instead of breaking, and tend to become distorted in manipula- 

 tion. Even the mouth-parts are evidently softer than in the 

 open-air genera. 



