Dicranomyia is one of the largest and most widely distributed genera within both the Limoniinae and the Tipuloidea as a whole. The current concept of Dicranomyia as displayed in the world catalog of Oosterbroek (2005) shows 23 subgeneric divisions. This large number of subgeneric divisions were created from the re-classification proposed in this catalog that moved numerous subgenera formally placed under Limonia to subgenera of Dicanomyia. The genus Dicranomyia in this current state does not offer a consistent synapomorphy by which the genus is based, rather this genus is best described as a extensive group of species that shows variation around a common groundplan of wing venation (see D. (Dicranomyia) Fig. 1) and male genetalia (see D. (Dicranomyia) Fig. 2). Further revision will likely see many of these subgenera transferred to other genera or elevated to the generic level.

Dicranomyia (Melanolimonia) is a variable group of species that does not possess a strong synapomorphy by with the subgenera is based. The most conspicuous characteristic of the subgenera is the dark melanized coloration of the body, including a typically polished black thorax covered with an extensive silvery pruinose pleura. Additional group defining morphological characters include the head with a typically prominent anterior vertex equipped with a silvery pleura, and the elongate Sc1 wing vein. The characteristics of the male hypopygium show a great deal of variation and offer no clear group defining characters. The 9th tergite has its posterior margin ranging from truncate to broadly emarginated with its posterior margins greatly produced to finger-like lobes. The gonostylus is bifid in a more or less typical Dicranomyia type, differing in the occasional bifid dorsal stylus and variation in the ventral stylus ranging from a near bifid condition to strongly obtuse and bulbous. A single stout rostral spine is typically present, though species with no rostral spines are common.