474 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxni. 



lobes, all three of the same width. The third segment has no dorsal 

 plates; the fourth has a pair whose combined area is greater than tliat 

 of the carapace, and which are separated by a deep posterior sinus, 

 often a trifle enlarged at its base. Genital segment transversely 

 elliptical, as large as the carapace, one-half wider than long, and 

 covered with a pair of huge dorsal plates, which overlap each other 

 along the mid-line, and extend back beyond the tip of the abdomen. 

 The posterior and the posterolateral borders of these plates and of 

 those on the fourth segment are toothed, the teeth on the genital 

 segment plates being considerably the larger and coarser. These 

 genital segment plates do not round over ventrally in a scroll like 

 those of Cecrops, but are flattened to the very edge. 



Abdomen similar to that in Cecrovs, the lateral lobes being pro- 

 longed sidewise and backward so that their edges coincide very 

 nearly with those of the genital segment plates. The length of the 

 abdomen plus these plates is about twice that of the genital segment 

 in front of the abdomen. The lobes are also set with fine teeth along 

 their margins, and are not rolled at the edges, but Hat. In conse- 

 quence, the space between them and the genital segment, in which 

 the egg-strings are coiled, is not as thick dorso-ventrally, but is wider 

 than in Cecrojis, and thus accommodates about the same length of 

 egg-strings, twenty or thirty times the length of the body. The 

 strings are about the same diameter and the eggs fully as numerous. 



First antennae three-jointed, the joints diminishing regularly in 

 diameter and in length from the base outward; they are very 

 sparsely armed with setae. Second antennae large, three- join ted, and 

 projecting well in front of the carapace; the terminal joint is a very 

 powerful and strongly curved claw, which is buried its entire length 

 in the flesh of the host. 



Mouth-tube broadly conical, similar to that in Cecroj^s, the man- 

 dibles projecting through the opening at its tip, armed with square 

 teeth on their inner margins only. Second maxilla^ in the form of 

 short conical knobs, apparently without joints, spines, or rudimen- 

 tary exopods. In size they are in sharp contrast -with those of the 

 preceding genus, being less than one-fourth of the length of the 

 mouth- tube. First maxillipeds two-jointed, both joints exception- 

 ally stout, the terminal one slightly the longer. The terminal claw 

 is short and wide and Ijeavily fringed with stout spines; the acces- 

 sory claw is in the form of a large spine. On the ventral surface of 

 the joint opposite the accessory claw is a raised knob covered with 

 small spines. Second maxillipeds swollen, the basal joint much 

 longer than the terminal claw; on its inner surface are two pairs of 

 knobs, one near the base of the terminal claw, and the other near 

 its own base; the claw when closed lies between the two knobs of 

 each pair. Legs all biramose, the rami transformed into flattened 



