The Pselaphid^ of North America. 253 



second palpal joint; the form of the head offers sexual differ- 

 ences in the vertex, but none in the eyes. Like Machasrites 

 it has a rudimentary second claw, short, nearly equal dorsal 

 segments, the two basal ventral segments prolonged, the 

 abdominal border narrow, and the first antennal and fourth 

 palpal joints cylindrical or four times longer than thick. Two 

 species are known to us. 



M. tychoides {TycJms bythinoides, Brend.) Chocolate - 

 brown, punctured, sparsely pubescent, antennae, palpi and 

 legs dark yellow. Length, 1.2 mm. Plate VII., Fig. 35, ?. 



Head strongly punctured, as wide as long, tempora shorter 

 than the large eyes, convergent, sides of the head anterior to 

 the eyes convergent; a fine line, parallel to the rather sharp 

 edge of the vertex, separates the middle part of the point from 

 the supra-antennal portion, and ends posteriorly in an irreg- 

 ular fovea. The strip between this line and the lateral edge 

 is fiat and roughened by transverse marks. Occiput and 

 interocular space evenly convex,, the convexity limited by a 

 line from the less convex inter-antennal space; there is no 

 median carina; the frontal margin is transverse, slightly 

 arcuate, suddenly declivous anteriorly. The declivity is exca- 

 vated on each side of the median septum, forming cavities for 

 the insertion of the antenna; the clypeus is divided by the 

 septum, and has a semicircular anterior margin. The last 

 palpal joint is securiform, more than three times longer than 

 its median width, the antennas not differing from those of the 

 next species. Prothorax punctate, widest in the middle, but 

 little wider than long, arcuately angled, with the sides nearly 

 straight from the middle to the neck and to the base. Base 

 twice as wide as the neck, near it being a faintly impressed 

 transverse line connecting the small lateral fove^e. Elytra 

 punctured, as wide across the shoulders as the prothorax, and 

 two- thirds wider across the tip. The suture is one -half 

 longer, sides anteriorly nearly straight, sutural lines parallel, 

 discal lines very short, faintly impressed. Abdomen shorter 

 than the elytra, dorsal segments equal, thighs clavate. Only 

 the female is known. 



