1864.] 
387 
marginal fringe of short white pubescence, interrupted on the middle 
of the segments ; on each extreme side of the sixth segment posteriorly, 
a short stout rather obtuse tooth; apical segment narrow, pointed, and 
carinated on each side above; beneath, the second ventral segment has 
its disk produced into a large somewhat acute tubercle ; posterior mar¬ 
gins of the third, fourth and fifth ventral segments carinated, the carina 
interrupted in the middle. Length 3J lines. 
Female .—U nknown. 
Hah. —Virginia. One specimen. Coll. Ent. Soc. Phila. 
Allied to A. pllosifrons n. sp., but not so hairy, the apical segment 
of the abdomen not so narrow, the projection of the second ventral 
segment much larger and more acute. The structure of the antennae 
is exactly the same in the two species. 
MONUMETHA, nov. gen. 
Head % transverse, as wide as the thorax, 9 subquadrate, rather wider than 
the thorax; ocelli placed in a curve on the vertex ,* antennae filiform, rather 
short; mandibles stout, deeply bifid at tip. Labial palpi four-jointed, two basal 
joints elongate, first joint rather more than half the length of the second; the 
two apical joints minute, about equal in length, slender at base, thickened and 
truncate at tip, placed at the side and near the apex of the second joint. Jlfaa;- 
illary palpi the two basal joints robust, first joint very short and 
about half the length of the second; third and fourth joints about equal in 
length and longer than the second joint; apical joint slender, cylindric, pointed 
at tip. Superior wings with one marginal and two submarginal cells, the second 
submarginal cell receiving the two recurrent nervures. Abdomen % sublinear, 
convex above, apex incurved, claws bifid; 9 subovate, rather short, furnished 
beneath with a short dense pollen-brush; claws simple. 
Also allied to Chelostoma and Herlades^ but distinct by Jive- 
jointed maxillary palpi. 
1. M. argentifrons, n. sp. 
Male .—Head black, finely punctured, clothed about the base of the 
antennae and on the vertex with long yellowish hairs; clypeus flat, 
clothed with short silvery-white decumbent pile, anterior margin trun¬ 
cate, and slightly emarginate in the middle; antennae black, rather 
short. Thorax black, clothed with rather long dense yellowish-white 
hairs. Wings hyaline, apical margins clouded, nervures black. Legs 
black, shining; anterior femora clothed beneath with long whitish 
hairs; tarsi clothed within with fuscous pubescence. Abdomen elou- 
