ART. 25 IITSECTS OF OKDER TRICHOPTERA MARTYNOV 17 



lary palpi in the male rather long, second joint approximately one- 

 half as long, slender. Spurs 2, 4, 4, the inner ones a little longer 

 than the outer ones. Anterior wings not very broad, resembling 

 those of the genus Dinarthrum McLachlan, with similar venation, 

 except the groove and apical veins; the groove along CuP is very 

 deep, reaching the anastomosis and concealing M in its interior; 

 discoidal cell long, Rs^ apparently detached at its base from RS3+4 

 and approximated to the end of the groove ; behind it there are four 

 apical branches, connected at their bases by an oblique vein; these 

 branches represent probably two branches of M, CuAj, and Ai. The 

 portion of the wing anterior to the groove is clothed with minute 

 blackish scales; apical portion clothed with hairs. Hind wings as in 

 Dinarthrwni. Male genital appendages resembling those of the 

 genus Dinarth^^n^ but the second joint of the inferior appendages is 

 longer, basal joint provided with a slender basal appendage; median 

 portion of the tenth segment not produced downward. 

 Type species. — Eodinarthrum pusilluir).^ new species. 



EODINARTHRUM PUSILLUM, new species 

 Plate 4, Figures 47 to 51 



The specimen examined is in poor condition; the wings are dam- 

 aged, and I could not make a figure of the hind one. 



Description. — Head brownish; basal joint of antennae yellowish 

 brown, somewhat thickened on its distal portion, bearing two 

 processes on the inner side, one basal and one distal, clothed with 

 numerous outstanding blackish hairs; basal portion of the joint 

 beai-s, together with hairs, a few elongated scales ; antennae approxi- 

 mately as long as the body, brownish, with indistinct yellow annula- 

 tions in its basal part. Maxillary palpi brownish, and clothed with 

 outstanding hairs. Thorax and abdomen brownish; legs brownish, 

 clothed with minute yellowish hairs; spurs 2, 4, 4, long. Anterior 

 wings brownish, clothed with yellowish hairs in their apical and 

 hind portions; anterior portion, between the groove and costal 

 vein, clothed with blackish scales; discoidal cell long; the groove 

 deep, concealing in its interior the greatest portion of M and of Cu ; 

 CuAo is apparently lacking, as in many species of Dinarthrum. 

 Posterior wings dark grayish. Male: Dorsal plate of the tenth seg- 

 ment similar to that of the genus Dinarthi'wn, but the median 

 (double) portion is somewhat more produced backward; if seen 

 from the side it is nearly triangular, without forming any dilation 

 or prominence (downward) in its apical portion. Basal joint of 

 the inferior appendages similar to that in the genus Dinarthrum^ 

 but from its base arises upward an additional slender process, as in 



