324 PROCEEDINGS OF THE NATIONAL MUSEUM vol.99 



thoracic segment overlying second as in female. Second thoracic 

 segment -with the lateral hyaline flange having larger tips than in the 

 female. Wing of third segment reaching to abont the middle of the 

 genital segment, inside margin rounded at the center, without a spin- 

 ous point as in the female; fourth segment separated dorsally, the 

 distal processes usually extending a little beyond the basis of the 

 abdomen, tipped with short spines. Fifth segment somewhat visible 

 dorsally. Eyes larger than those of female. 



Urosome very slender; proportions of genital and anal segments 2 

 to 1 as in female, but segments relatively longer and the caudal rami 

 relatively shorter; approximate proportions, lateral view, ventral side : 

 26: 13:30. Ventral hook of genital segment large (pi. 18, fig. 11) ; 

 lobed genital flaps with two rows of fine hairs on the surface, the 

 seta long, nonplumose, accompanied inside by a stout median spine 

 and a short process with a broadened base (pi. 18, fig. 10). Caudal 

 rami about three-fourths the length of the abdomen, with a short 

 lateral seta distally; terminal setae 3 (pi. 18, fig. 14), the inner the 

 longest, stout and spiniform, equaling the ramus in length and adding 

 to the superficial appearance of great length of the urosome; the 

 outer also spiniform, about one-fourth as long as the inner ; the third 

 slightly longer, slender and sinuous, placed subterminally near the 

 dorsal inner edge. 



Second antenna (pi. 18, fig. 8) with the basal segment about half the 

 length of the second; its spine finely serrate and about as long as 

 the second segment. Lamina on inner margin of second segment 

 with a stout outer spinous process, the central portion of the lamina 

 very thin, but produced into a second spinous projection ; surface of 

 segment near middle with a row of minute teeth, hardly visible except 

 at high magnification ; spine with stout barbules which are most thickly 

 set in the central portion. Third segment with the basal process very 

 slender, its tip divided, reaching about to the end of the segment. 

 Accessory claw stout basally, otherwise very slender, reaching by al- 

 most half its own length beyond the base of the terminal claw; its 

 tip also divided; a secondary spine, with a 3-pronged apex, at its 

 base. Terminal claw stout, blunt ended, slightly exceeding in length 

 the two basal segments combined. 



Exopod of first leg (pi. 18, fig. 9) having the distal part of the 

 terminal inside spine a little recurved, but the whole directed in- 

 ward, the apex of the segment being incised centrally for a short 

 distance, the resulting two portions having each a hyaline, foliate 

 structure inside; this whole condition suggested in the female, but 

 much more strongly developed in the male. The hyaline flanges of 

 the outer margin of the segment minutely serrate; that of the distal 

 portion rather short due to the excessive development of the distal 



