Bromophila Loew, 1873 is one of nearly two dozen genera in the Afrotropical region with only a few species. In this case there is a single species, so Bromophila is referred to as monotypic. The type species is Bromophila caffra (Macquart, 1846). The authority i.e. Macquart, is in brackets because he originally placed the species caffra in another genus (Dichromyia) and it was subsequently moved to Bromophila. The type was described from South Africa, but in fact this species is spread across most of the southern and eastern part of the continent.
A second name, B. zamiel (Walker, 1849), was proposed for material from South Africa, but this is a junior subjective synonym of Bromophila caffra (Macquart, 1846).
Uniquely among signal flies, Bromophila caffra lacks ocelli - the three small lenses on top of the head that are responsible for metering light levels. The black arrow indicates the position where the ocellar triangle is usually found in all other signal flies.
Another character, which appears to be unique to the genus is the form of the male sexual appendage, that is the aedeagus or phallus. In Platystomatidae this is an elongate coiled structure, often with terminal filaments. These filaments are coiled up inside a genital cavity at the apex of tergite five. In Bromophila caffra the terminal filaments are paired and unusually barbed. Not only that, but the two are asymmetrical; both are barbed along the length of the filament and in addition one filament ends in a complex 3 dimensional arrangements of barbs.
In the images below cerc = cersus; epand = epandrium; f1 = filament 1; f2 = filament 2;
gc = genital cavity; ph = phallus; S8 = sternite 8; T5 = tergite 5.
Loew, H. 1873. Monographs of the Diptera of North America. Part III. Smithsonian miscellaneous Collections 11 (No. 256): vii = 1 - 351.
Macquart, J. 1846. Diptères exotiques nouveaux ou peu connus. Supplément. Mém Soc. Sci. Agric. Lille 1844: 133 - 364.
Steyskal, G.C. 1980. 43. Family Platystomatidae. In: Crosskey, R.W., ed., Catalogue of the Diptera of the Afrotropical Region. London: British Museum (Natural History), pp. 563–574.
Walker, F. 1849. List of the specimens of dipterous insects in the collection of the British Museum. British Museum, London. Part III: 485 - 687.