grata Curran, 1941 [incertae sedis]

Figs 40–43.

Baccha grata Curran, 1941: 270 . Type-locality: Brazil, Mato Grosso, Chapada [HT ♀ AMNH].

Ocyptamus gratus . Thompson et al. (1976: 19).

Comments. After studying specimens at the CNC identified as grata Curran, the male genitalia and wing characters are similar to the ones of placiva and conjunctus (see comments below in placiva). The abdominal markings are similar to those two species, but grata has an only slightly petiolate abdomen and its basoflagellomere is remarkably bifurcated in both sexes (a character seen so far in species of the subfamily Microdontinae and in the genus Cacoceria Hull of the Eristalinae). Other unique characters of this species are the male abdominal segment 5 and genitalia flexed dorsally, positioned perpendicular to the rest of the abdomen, tergum 4 with deep concave apical margin and sternum 4 with pair of acute projections apically. The female terga 5 and 6 are slightly asymmetric. It is unfortunate that when Curran (1941) described this species his type specimen lacked its most distinctive attributes, i.e. the basoflagellomere and the apex of the abdomen, partly destroyed by pests.