Xanthandrus (Androsyrphus) Thompson, 1981.
Thompson, F.C. (1981) The flower flies of the West Indies (Diptera: Syrphidae). Memoirs of the Entomological Society of Washington 9, 200 pp. [1981.09.02]
Adapted from original description (Thompson 1981).
MALE.
Head black; face tuberculate, straight except for tubercle; facial tubercle small, rounded, abrupt; ocellar triangle about twice its length anterior to posterior eye margin; eye bare; basoflagellomere elongate oval; arista bare.
Thorax with anterior anepisternum bare; katepisternum with pile patches broadly separated; scutellum with distinct premarginal sulcus, with ventral fringe long and abundant; metasternum bare, developed as in Platycheirus; postmetacoxal pile patch present; metapleuron bare; all femora slightly swollen with metafemur distinctly swollen, with long ventral spinose setae on apical 1/2 of middle and apical 5/6 of metafemur; metatibia slightly arcuate; wing venation typical of Xanthandrus comtus (Harris).
Abdomen elongate, about 3x as long as broad; dorsum with large orange maculae; male with 5 pregenital segments; cercus flattened, densely pilose; surstyle simple, rectangular, slightly curved mesially on apical 1/3, with a vertical carina on mesial surface on apical 1/3; 9th sternum with a prominent ventromedial lateral flange; lingula broad, short, with anterior edge double convex; superior lobe free, not sickle-shaped, elongate, lobate; aedeagus simple, tubular.
unless otherwise stated