1887.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 565 



outward and downward. The anterior part of each lobe is much thick- 

 ened, while the ends are thin, and more or less extended, the inner ones 

 somewhat the longest and reaching about to tlie caudal segment. The 

 shape of these appendages may change considerably in alcoholic spec- 

 imens. Tlie thoracic feet of the fourth pair are very elongate, folia- 

 ceous, bilobed. They originate just in front of tbe genital ring, and eacii 

 consists of one principal process and an inner, shorter one. Tiie former 

 is rather broad, subliiiu'colate in outline, nnrrow toward the base, be- 

 coming broadest near tlie middle, and tapering from there toward the 

 hinder end, wliicli is rounded. Its greatest width is e({ual to about one- 

 fourtli its length or slightly more, and it projects for fully one-half its 

 length back of the posterior extremity of the dorsal shield. Tlie inner 

 process is nu elongate lobe, rounded posteriorly, and with a convex 

 inner margin, which originates at the posterior extremity of the thorax; 

 the outer margin is only a.bout one-half as long as the iiuier margin, 

 and merges into the ventral surface of the outer process about one-third 

 the length of the latter from its base. The length of the inner process, 

 as measured on its longer margin, is about two and one-half times its 

 greatest width, and a little more than one-halt the length of the outer 

 process. It extends a short distance back of the posterior extremity 

 of the dorsal shield. 



The abdomen is very small, with few, slight, transverse constrictions. 

 It is located under the front part ot the dorsal shield. The caudal seg- 

 ment is short, simple, nearly square in transverse section, and termi- 

 nates in two very small conical or rounded knobs, one on each side. 



The egg-tubes are slender, approximately straight, and may equal in 

 length the entire body with its appendages. 



The microscopic appendages are as follows : The anterior antenna) 

 are very small, slender, rounded, and originate on the front margin of 

 thecephalothorax, near the dorsal surface and at some distance from the 

 middle. They are generally folded against the surface, but when raised 

 l)roject slightly beyond the sides, and consist apparently of three joints 

 of which the basal is much the largest and the distal the smallest. The 

 latter terminates in two or more small rounded knobs and numerous 

 papillae ; two similar papilhe also arise from the front side of the median 

 joint. The posterior antenn;e or prehensde claws consist of a very large 

 basal joint, broad at the base and rapidly tapering, and a much smaller, 

 rather slender, curved and sharply pointed terminal joint. The details 

 of the horny frame- work to which they are attached arc represented in 

 Fig. ], Plate XXXIL The proboscis is elongate, conical in shape, be- 

 coming quite slender near the tip which is small, rounded. Tbe palpi 

 (maxilliX)) consist of an elongate terminal joint, armed at the tip with 

 two slender acute spines, one of which is jointed, the otlier not, and, 

 apparently, of one irregular basal joint, with a small jointed spine pro- 

 jecting from the posterior margin. 



