There are one male and two female syntypes of Milichiella lacteipennis in MCZ. The male which has been photographed (Type 13451, Anonymous 2009) was designated as lectotype by Brake (2009).

There is one female ST of M. nitida in BMNH. Walker did not state the number or sex of the type specimens of M. nitida. The female specimen in BMNH was designated as the lectotype by Brake (2009) to permit synonymy of M. nitida with M. lacteipennis. Gymnopa nitida Walker, 1836 is thus the senior synonym of M. lacteipennis. However, the name Gymnopa nitida has not been used in original literature after 1899 (only in catalogues), whereas the name Milichiella lacteipennis has been in frequent use. M. lacteipennis is therefore designated as the valid name following ICZN Art. 23.9. Photographs of the male ST of M. lacteipennis are shown in the MCZ type database.

Specimens studied by Brake (2009) were collected on goat, dairy cattle and pig dung, manure piles, grass clippings, garden compost, flowers of Donnellsmithia hintonii M&G., Asclepias, Baccharis glutinosa, Ochradenus baccatus, Tamarix, and leaves of pawpaw, and in Malaise, light, flight, pan, pit fall, carrion, and dung traps. Habitats are arid zones, beach forest, forest edges, mountain meadows and ponderosa pine/meadow. Flies were bred from decaying banana skins and ground-nut plots. Milichiella lacteipennis was observed swarming beside cactus and was attracted by raw or linseed oil or paint.