VEGA-EXPEDITIONENS VETENSKAPLIGA ARBETEN. 830 
taceous, broad laterally, the apex upcurved and furnished with 
three bristles proceeding from denticulations of the edge, and 
on the upper edge near the base are about four similar bristles 
and denticulations on a dilated portion. Penis broad, flat, ob- 
tuse, placed below the last-named appendages. Inferior append- 
ages large, widely divergent, rather narrow at the base, but 
gradually dilated so that the extremities are broad and very 
obtuse, convex externally and concave internally, fringed with 
long yellowish hairs; on the upper edge, near the apex, there 
is a deep excision in which is a strong curved spine and one 
or two ridges or teeth (precise conformation of this structure 
is difficult to disceriminate). No ventral teeth. 
Expanse about 15 mm. 
The above description is taken from dry examples. 
In examples of the & in alcohol the abdomen above and 
beneath presents blackish chitinous plates separated by broad 
pale segmental divisions. 
The only 2 (in alcohol) has the abdomen elongated, and 
the wings apparently somewhat abbreviated. 
M. scissum is distinet from all the described species of the 
genus in the form of the anal parts of the &£, and especially 
in the divided »dorsal lobe>, which finds no parallel in any 
known species. This is satisfactory because the genus is one 
of the most difficult in which to define the species with any 
approach to certainty. 
Micrasema sp. nov. — One 2 from Port Clarence, Alaska, 
0 is Tabundantly distinet from M.; scssum, but it is 
useless to give it a name in the absence of the sg. Judging 
from the example in alcohol it should be nearly entirely of a 
yellowish hue instead of the dark colour usual in the genus. 
The generic position appears certain, and the genus is becoming 
of great interest in consequence of the position itis gradually 
acquiring in the arctic insect-fauna. 
Ö 
