THE PsELAPHIDZ 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 Macherites 
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. tycuorwEs (Zychus bythinoides, Brend.) Chocolate - 
brown, punctured, sparsely pubescent, antennz, palpi and 
legs dark yellow. Length, 1.2 mm. Plate VII., Fig. 35, 9. 
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 flat 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 antennz; 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 antenne 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 fovee. E/ytra 
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. Addomen shorter 
than the elytra, dorsal segments equal, thighs clavate. Only 
the female is known. 
