Hesse (1969) described this species as follows: Body mainly dark or black, but the head above, frons and face in female, the pleurae to a variable extent in both sexes, the darker parts of abdomen in female and to a variable and obscure extent segments 2-4 of abdomen in male more dark reddish brownish to reddish; antennae mainly reddish brownish to dark reddish brownish, the clubs more orange yellowish; clypeus reddish to reddish brownish; proboscis also mainly reddish brownish; humeral tubercles, especially in female, reddish; an infusion on inner sides of humeral tubercles, extending discally on thorax as a submedial streak on each side to beyond middle in female and to a lesser extent sides of thorax, reddish; postalar calli and hind margin of scutellum, as well as to a variable extent sides of metanotum, reddish in both sexes; broad discal parts of tergites 2-5 or 6 in female strikingly orange-yellowish, the last three tergites in some females reddish like sides and venter; hind margins of tergites 1-4 in male and 1-5 in female appearing reddish, and the rest darker reddish; middle tergites of abdomen above in male sometimes with an indication of a faint and obscure central yellowish line; bullae narrowish, yellowish reddish; hypopygium of male mainly yellowish; last segment in female sometimes paler reddish than rest of darker red on abdomen; legs, except coxae, mainly yellowish brownish, the hind femora somewhat darkened along upper and inner upper aspect. Integument of middle part of frons, clypeus, much of pleurae, narrow anterior margin of tergite-1, depression between 1 and 2 in both sexes shining; that of abdomen, especially in male, with very fine areolar microsculpture, but sides of abdomen, last two or three segments, and venter in female however also more or less shining, and last three segments in male also somewhat shining, the rest being dulled by the fine microsculpture; integument of thorax above dull, due to fine rugulose sculpture in three broadish streaks, separated submedially on each side by a narrower streak of setiferous granules and coarser rugae posteriorly, the sides of thorax smoother, with more widely separated oblique rugae; tergite-1 rather markedly depressed medially and, in female, last two segments somewhat transversely wrinkled; integument of legs dull. Vestiture poorly developed, even in male; longish hairs on head in front in male and shorter and sparser ones in female reddish brownish; short ones in streaks on thorax above more fulvous to fulvous brownish; sparse, longish ones on propleural knob, and short, sparse, scarcely discernible ones in front of halteres and sides of tergite-1 also fulvous brownish, shorter in female; fine and short hairs on rest of tergite-1 dark or brownish, sparser in female; rest of fine ones on abdomen in male also fulvous brownish, sparser, but becoming longer on last three segments and hypopygium, almost absent on segments 4-6 in female, but longer and darker, more chocolate brownish on last two segments and genital segments; hairs on legs short, sparse and dark, slightly paler reddish or fulvous on tibiae; spines and spicules on legs reddish to reddish fulvous. Head with the antennae rather long, very much longer than thorax (excluding scutellum); segment-1 about 2.5—2.8 times length of 2; segment 3 elongate, only slightly thickened apically; club elongate and together with articulating segment-like junction scarcely shorter than, or about as long as, 3 and with less than its basal fourth constricted, also slightly narrowed beyond middle before broadened apical part; proboscis slender, shorter than thorax, but slightly longer than vertical length of eye; palps distinctly longer than antennal segment-2. Wings tinted yellowish brownish, darker and more brownish in female, the apex and hind border in both sexes slightly clearer; veins reddish brownish, more yellowish in hinder half; apex of discoidal cell shortly stalked; hind margin of squamae brownish; halteres reddish brownish to dark brownish. Legs with the hind ones rather long; hind femora slightly, but distinctly, thickened, armed below with a double row of spines from just before middle, without any spines on sides above apically; front and middle tibiae rather curved, more so in male, the hind ones curved beyond middle; basal segment of hind tarsi distinctly longer than claw-segment. Oviscape in female with about 9 or 10 fulvous reddish spines on a side. Hypopygium of male with the anal lobes shortish, their combined apical margin rather deeply and angularly indented; lobes of tergite-9 broadly and truncately rounded, apically mainly smooth; sternite-9 relatively large, smooth, keeled centrally posteriorly, its processes mainly smooth, somewhat flattened or slightly depressed above. Length of body: about 13-15 mm; Length of wing: about 9-11 mm.

Unknown.

Type locality: South Africa, Northern Cape in Springbok.

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, Namaqualand. Springbok (Lightfoot, Oct. 1890) (female holotype and male allotype); Springbok (Lightfoot, Nov. 1890) (male paratype); Okiep (Lightfoot, Sept. 1890) (female paratype) (Hesse 1969).

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).

Succulent Karoo.