296 Annals Entomological Society of America [Vol. XV, 



Adult Female. — Resembles impressus in most of its features. AntenncTs 

 as below: 



1st joint, length 0.224 mm.; 



2d joint, length 0.544 mm.; diameter 0.20S mm. 



3d joint, length 0.512 mm.; diameter 0.20S mm. 



4th joint, length 0.448 mm.; diameter 208 mm. 



5th joint, length 0.448 mm.; diameter 0.240 mm. 



6th .joint, length 432 mm.; diameter 256 mm. 



7th-8th joint, length 0.096 mm. 



Total length 2 . 704 mm.. 



Mandibtilar stipe truncate, but scarcely angular below. Lateral 

 lobes of first segment not evenly rounded, a posterior angle being 

 obvious. The second and third segments are appreciably more swollen, 

 in relation with the larger size of the vulva (Figs. 43, 44). The posterior 

 ventral margin of the second segment is raised and rounded, causing 

 the ventral dimple to be almost as long as broad, trapeziform (Fig. 

 45, .4). The third segment is much longer ventrally than dorsally; 

 the inner pleural margins are parallel and nearly straight; but the 

 ventral lobes are so small and so widely separated that the vulvar 

 aperture is practically open backwards and reaches as far back as the 

 fourth segment, (Fig. 44). 



The vulvae are uncommonly large (Fig. 46, 47). H. C. Wood 

 (1865, p. 197, Fig. 29) has issued a description and a drawing of these 

 organs which, though reduced are perfectly appropriate; yet he fails to 

 mention that the "flattened cylinders" are coalesced. Compared with 

 the similar organ of impressus, the synoperculum is more quadrate, its 

 outer margins being perpendicular (slightly emarginate) and its breadth 

 hardly different distally and proximally. The median notch is larger, 

 with rounded bottom. The edges of the heart-shaped projection 

 (H, Fig. 47) are considerably expanded into broad, flattened triangular 

 lobes, reaching laterally the outer margins of the synoperculum and 

 overlapping the distal half of the excavations in which the mounds are 

 sheltered; the outer margins of the lobes converge towards the base 

 of the synoperculum without meeting,' entirely disjoining the mounds. 



The "pair of very slender, almost filiform, feet-like bodies" men- 

 tioned by Wood in connection with the synoperculum, are the atrophied 

 limbs of the second pair which are fastened to its anterior surface. As 

 in impressus the six joints are preserved, being broader than long and 

 of irregular size. In addition a small sternal plate was present in the 

 specimen examined. 



The lateral outline of the mound reminds of a crescent, the lower, 

 rounded end of which is abruptly bent inwardly below the mound 

 (Fig. 48). A narrow cleft divides the organ into two subequal halves, 

 which are only connected caudad by the reflexed end of the crescent 

 (h, Fig. 49), this being equivalent to the horse-shoe. No dividing 

 sulcus exist between the latter and the valves. CejDhalad each valve 

 bears a sharp diagonal crest, both crests meeting at the anterior end 

 of the crescent. The anterior region of the inner valve which faces 



