Halictus basalis

Smith, F., 1857, Catalogue of the hymenopterous insects collected at Sarawak, Borneo; Mount Ophir, Malacca; and at Singapore, by A. R. Wallace., Journal of the Proceedings of the Linnean Society of London, Zoology 2, pp. 42-88 : 43

3. Halictus basalis .

H. niger; alis hyalinis; abdomine clavato, basi ferrugineo.

Male. Length 3 lines. Black: the antennae nearly as long as the thorax, the flagellum fulvous beneath; the face covered with a dense griseous pubescence; the mandibles rufo-piceous. Thorax thinly clothed with pale pubescence; the wings hyaline and iridescent, the nervures pale testaceous; the tibiae and tarsi pale rufo-testaceous, the latter palest. Abdomen clavate, shining and finely punctured; the first segment and the apical margin of the second, ferruginous; the second and following segments with fasciae of pale pubescence.

Hab. Singapore.

This conspicuous insect might be mistaken at first sight for a variety of "H. ceratinus," but in that species the apical margin of the fifth segment of the abdomen, beneath, is straight, or very slightly emarginate at the sides; in the present species it is deeply emarginate its entire width.