Specimens of the variety differ in having hyaline wings, a black abdominal tip, and wider and shorter S5.

Milichiella arcuata has been collected at light, in Malaise and carrion traps, in Opuntia fields, in damp secondary growth in Acer-Betula woods, on carrion, at windows, on charred trunks, egg plants, and resting on blossoms of Lactuca scariola var. integrata (Asteraceae). It has been reared from a chicken pen. The species is fairly common and has been collected May to September in the north and February to December in the south.

Milichiella arcuata var. has been collected in wild mushroom traps, “ADg. traps”, mushroom traps [under] Palmetto shrubs (Arecaceae), and Malaise traps. A questionable specimen of this variety emerged from the detritus of a gopher tortoise burrow.