Hesse (1969) described this species as follows: Body also mainly dark or dark blackish brown, but with the broad hinder discal parts of tergites 2-4 in both sexes to a variable extent, or sometimes in male with entire discal parts of these tergites, orange yellowish or ochreous yellowish as in female of A. namaquensis; abdomen posteriorly in female very dark reddish brownish; vertex on each side, clypeus, especially in female, head below, proboscis below, humeral tubercles in $ and an infusion on anterior part of thorax above on inner sides of humeral tubercles in $, as well as an obscure and abbreviated submedial streak on each side in female, postalar calli, especially in female, hinder parts of pleurae to a variable extent, extreme sides of tergite-1 and hind margins of 1-6 to a variable extent dark reddish; antennae mainly yellowish brownish to reddish brownish, the clubs more yellowish or orange yellowish ; bullae reddish to dark reddish brownish to almost black, rather small and narrowish in both sexes, very broadly separated in female; venter more yellowish up to end of sternite-4 in male and 3 in female; hypopygial structures reddish brownish, sternite-9 paler, with more yellowish; legs mainly reddish brownish, the femora darker above and the tibiae and tarsi somewhat paler reddish or yellowish reddish. Integument of middle part of head in front, clypeus, greater part of pleurae, junction between tergites-1 and -2, more especially last three segments of abdomen in male and last four in female, more or less shining; integument of thorax above rugulose, finer in a broadish streak along sides (not extreme sides) and along middle as in A. namaquensis; integument of abdomen very finely areolar-micro-sculptured, and in female last two segments were obscurely transversely wrinkled; femora also shallowly transversely annulate. Vestiture slightly longer and denser than in A. namaquensis, the hairs on head, pleurae and sides of tergite-1 being slightly longer and denser; hairs on these sites sparser and shorter in female than in male; those on head, thorax, pleurae and greater part of abdomen in male whitish, those from tergite-3 to apex sparse; hairs on these sites in female more fulvous brownish to brown, but almost absent on tergites 3-6; reversed hairs on last two segments in female blackish brownish; hairs on hypopygium fulvous brownish; those on legs sparse and short in both sexes, paler or whitish in male, more yellowish brownish or brown in female; spines and spicules on legs fulvous yellowish. Head with the antennae proportionally shorter, though also much longer than thorax; segment-1 relatively short, scarcely thickened, about 2-2-2-4 times length of 2; segment-3 slender, proportionally shorter than in A. namaquensis, apically only slightly thickened, slightly longer than club itself, but slightly shorter than club plus articulating part; club rather thickened knob-like beyond middle, more rapidly so than in A. namaquensis, its base constricted; proboscis slender, slightly longer than thorax (excluding scutellum); palps distinct, quite as, or nearly as, long as antennal segment-1. Wings relatively shortish and broad, more so than in A. namaquensis, tinted brownish, slightly darker in female and in hinder half more evident as infusions along the veins, the cells in this part appearing clearer in middle and apex and hind border also much clearer; veins brownish to dark reddish brownish; apex of first posterior cell rather angularly narrowed, much more so than in A. namaquensis; apex of discoidal cell very shortly stalked or sometimes meeting third posterior cell at a point; halteres dark brownish. Legs relatively shorter than in A. namaquensis, with the hind femora slightly clavately thickened, armed below with a double row of spines on tubercles from just before middle, without any dorso-apical or latero-apical ones; tarsi rather shortish ; basal segment of hind tarsi much longer than claw-segment; apices of claws more rapidly curved down in male than in female, more obviously so than in A. namaquensis. Oviscape in female with 7 or 8 slender fulvous spines on a side. Hypopygium of male very much like that of A. namaquensis, but anal lobes relatively narrower, the lobes of tergite-9 more rounded apically, not so truncately rounded; the other structures very similar. Length of body: about 11-15 mm; Length of wing: about 7.5-10.0 mm.

This species closely resembles A. namaquensis, but main distinguishing features are included in the morphological descriptions (Hesse 1969).

Type locality: South Africa, Northern Cape at Jackals Water.

Arenomydas is southern African endemic genus with about 9 described species, with one record from southern Namibia (Kirk-Spriggs and Sinclair 2017).

South Africa.

South Africa, Northern Cape, Jackals Water (Jakkalswater) (Lightfoot, Oct. 1911) (types and paratype).

The information below was extracted from Cannings and Scudder (2005): Dipterans are primarily aerial insects and the mesothorax, which bears the only pair of wings, dominates the thorax - the prothorax and metathorax are greatly reduced. The legs are normally rather simple and are used primarily for perching; in some groups, they are modified for prey capture or for signaling during courtship. The tarsi are nearly always 5-segmented. The functional wings are membranous and their pattern of veins is critical in fly classification and identification. During the evolution of flies, there has been a trend towards a reduction in veins, especially in the rear half of the wing – changes that evidently relate to improvements in two-winged flight. The hindwings, present in most other insects, are reduced in Diptera to small, club-like organs, called halteres, used for stabilising flight.

Herbivore - Nectarivore (nectar-eating)

The flies in this family are not known to hunt, catch or prey upon other insects as asilids do, but mainly feed on nectar (Hesse 1969).

Like the others, flies in the Mydidae family begin life as an egg, which hatches into a grub-like larva. Most of the fly life is spent in the larval stage, mainly eating and growing, as well as molting several times. Some flies may spend at least a year as a larva. The next stage is a pupa, during which the insect transforms into its final stage, emerging from the pupa as a winged adult, able to mate and reproduce. In many species, males stake out positions at favourable egg-laying sites and wait for females to arrive (Hesse 1969).

Specimens have been collected from September - November (very few records for August and December) (Kirk-Spriggs and Sinclair 2017).