Length 10 mm.; alar expanse 15 mm. — The head black, shining and impunctate, thinly covered with whitish hairs, more densely covered with silvery hairs on the clypeus; a sharp carina between the antennae; the scape of the antennae, the palpi and the mandibles yellowish, the latter with brown tips; the flagellum of the antennae black above, pale ferrugineous beneath. The thorax black, covered with rather long erect whitish hairs; the mesothorax shining and nearly impunctate; the metathorax clathrate-rugose, with a deep longitudinal furrow across the middle, and at both sides of this furrow, a little behind the postscutellum, a very glossy and impunctate space. The tegulae pale ferrugineous, and a small spot before the base of the wings pale yellow. The wings hyaline and beautifully iridescent, the stigma and nervures dark brown. The second submarginal cell does not receive the first recurrent nervure, this nervure joining the cubital one a little before the apex of the first submarginal cell. The legs thinly covered with erect hairs; the anterior and intermediate pair pale yellow, with exception of the coxae and femora which are dark brown; the posterior legs dark brown, with the trochanters and the base of the tibiae as well as the apical spines pale yellow.