NO. 1788. NORTH AMERICAN EROASILIDM— WILSON. 337 



ERGASILUS MANICATUS, new species. 

 Plate 44, text figures 1 and 5. 



Female. — Head and first thorax segment completely fused, with 

 no visible indication of the union except in the young. 



Resultant cephalothorax elliptical, strongly arched dorsally, one- 

 fifth longer than wide, projecting anteriorly in a large median rostrum, 

 and produced posteriorly into a small lobe on either side of the first 

 free segment. The latter only two-fifths the width of the carapace; 

 third, fourth, and fifth segments diminishing regularly in width and 

 length, the fifth being almost entirely concealed between the fourth 

 and genital segments, especially in mature adults. Genital segment 

 narrower than even this fifth segment and about half as long as all the 

 free segments combined; barrel shaped with its sides evenly rounded. 

 Egg-sacks relatively large, each of them longer than the entire body 

 and four-fifths as wide, and tapered posteriorly; eggs large, arranged 

 in four or five longitudinal rows, about fifty or sixty in each sack. 



Abdomen the same length as the genital segment, three-jointed, 

 with the joints equal. Anal laminae rectangular, about as long as the 

 last abdomen joint, each tipped with two setae, of which the inner is 

 three times the length of the outer. 



First antennae six-jointed, the joints of unequal lengths and 

 wddths, the five basal ones sparsely armed with setae, the terminal 

 one tipped with a tuft of about a dozen (fig. 5 and 71). 



The basal joint is curiously grooved, so as to appear like three 

 joints, or to be made up of three parts, according to the point of view. 

 But in dorsal view the grooves are concentric and show that they are 

 not dividing lines between joints. 



Second antennae four jointed, each of the two basal joints being 

 prolonged into a large sleeve or hood, covering the dorsal surface of 

 the joint succeeding it. The basal joint itself is triangular, one angle 

 fastened to the ventral surface of the carapace, and the distal end a 

 side. The second joint is attached to the anterior corner of this 

 side, while the whole side is produced into a semielliptical flap or 

 sleeve, twice the width of the second segment and covering the whole 

 of its dorsal surface. In its turn the distal end of the second joint 

 is enlarged to twice the diameter of the third joint, and produced 

 into a sleeve covering the proximal end of the dorsal surface of the 

 latter for about one-third of its length. The third joint is consid- 

 erably narrower than the second, of the same diameter throughout, 

 and without any sleeve or projection. The terminal joint is in the 

 form of a stout claw, \vitli an accessory tooth on its inner margin near 

 the base. 



Mouth-parts projecting quite strongly; mandibles with a short 

 basal joint which is divided through the center longitudinally by an 

 Proc.N.M.vol.39— 10 24 



