North American Centropagidce. 231 



than any of the others except the fifth, which is the shortest : 

 the second, third, and fourth segments decreasing in length 

 in regular order ; the second slightly shorter than the furcal 

 rami, which are armed as in the female. 



Antenna? 23-segmented, extending about to the end of the 

 cephalothorax, or barely surpassing it. Eight male antenna 

 geniculate between the 18th and 19th segments; 19th and 

 20th segments ankylosed; six segments preceding the genieu- 

 lation rather thickly swollen; penultimate segment produced 

 at the inner apical angle into a broad bluntly-rounded process 

 extending slightly beyond the end of the segment. 



Fifth pair of legs of male biramose. Second basal segment 

 of right leg armed above the middle of the outer margin with 

 a delicate hair slanting upward. First segment of outer 

 ramus slightly longer than the width at the base, irregularly 

 trapezoidal, the outer margin forming the longest side ; armed 

 at the outer apical angle with a stout spine about as long as 

 the segment itself and provided on ea-ch margin with a nar- 

 row hyaline lamella; just within this, another very minute 

 spine. Second segment irregular in form, the proximal third 

 subquadrate, about as wide as the preceding segment, pro- 

 duced at the inner apical angle in the form of a rather large 

 cushion-like pad sparsely covered with delicate hairs ; distal 

 two thirds subquadrate, about half as wide as the proximal 

 third, provided on the inner margin with delicate hairs, and 

 armed a short distance above the middle of the outer margin 

 with two spines, one large and one small, similar to those on 

 the preceding segment; apex of segment armed with three 

 spines fully as long as the segment itself, the outer two 

 straight, the inner curved inward slightly, and each of them 

 provided with a hyaline lamella, the edges of which seem to be 

 plumose. Just posterior to the inner apical seta is a short 

 slender spine. 



First segment of inner ramus of right leg irregular in form, 

 about as long as wide, provided on the inner margin with a 

 few fine hairs. 'Second segment slightly wider than the pre- 

 ceding, barrel-shaped, and slightly longer than wide; pro- 

 vided on the inner margin with a few fine hairs, and at the 



