DIPTERA > BRACHYCERA | Higher Diptera

MUSCOMORPHA > SCHIZOPHORA > Calyptratae > Muscoidea > Anthomyiidae (246 species)

(subfamilies: Anthomyiinae and Pegomyiinae)

A large, extremely diverse family of generally drab, rather nondescript, small to medium-sized flies that in many cases resemble muscids, although typically with a slimmer, less robust appearance. Identification can be difficult and challenging even under a microscope as the majority of anthomyiids require examination of body bristles and/or male genitalia. Females of many species cannot be determined unless seen or collected with males. Consequently, it's fair to say that trying to identify the species or even determining the correct genus from photos is mostly impossible. There are a couple of exceptions where certain species can be determined to some degree, as discussed on the following pages but, even for personal records, they should all be regarded as tentative - 'likely' or 'possibly' at best.

Although the larval habits of the family are varied, most species develop in the stems and roots of both living and decaying plants, hence the common name of root-maggot flies. Some however, such as the Anthomyia species, breed in bird's nests, whilst others feed on fungus. The adults of many species are often seen visiting flowers or resting on sun-lit leaves, and are often some of the most abundant species in certain habitats, such as woodland and saltmarsh.

Their wing venation is fairly constant and, from a purely visual check, it's probably the best place to start when trying to confirm that a particular individual is actually an anthomyiid rather than a muscid. You need to be able to clearly see the veins though, as one of the most important characteristics of these species is that the anal vein reaches, or very nearly reaches, the wing margin. Additionally, vein M1 is pretty much straight with no noticeable curve towards R4+5, thereby leaving that cell broadly open at the wing tip. A further distinguishing feature is that in most species the underside of the scutellum is distinctly hairy but, in practice from a photographer's point of view, that detail may or not be visible. I really struggled recognising these species when I first started photographing flies back in 2021/22 but, as my knowledge has grown, I've found that, more often than not, I can tell I'm looking at an anthomyiid simply from its 'jizz' - colour and shape.

The general characteristics of the family are quite extensive, described as: small to relatively large (4-12mm) slender flies; more often coloured brownish, greyish or blackish, although sometimes yellowish, or with a distinct pattern on the thorax and abdomen, but never with a metallic sheen; their compound eyes are usually well-separated in females, but often meeting above in males; the antennae have quadrate or oblong third segments, and the arista is bare to plumose; the frons bears frontal, vertical and ocellar bristles; vibrissae are present; females often with interfrontal bristles; wings generally clear, sometimes tinged, but rarely marked; venation virtually always with straight vein M1 and long anal veins; the costa reaches the tip of vein M1, cell r4+5 always wide open, and vein A1 long and usually traceable to the wing margin; the scutum normally has paired postsutural acrostichal bristles, one or two pairs of pre-sutural dorsocentral bristles and one to four pairs of post-sutural dorsocentrals; there are always two notopleural bristles; the scutellum has a pair of basal and a pair of apical bristles; hypopleuron (meron) devoid of bristles near hind margin; legs are slender and bristly, the base of the first segment of the hind tarsus bears a strong bristle underneath; the abdomen is usually cylindrical and more or less conical; sternite five in males is bilobed; the female ovipositor is usually tubular.

The classification and taxonomic arrangement of the family, followed by a list of the most frequently recorded species, is shown on the next page. Species that I've photographed and have been able to identify to some level, namely of the genera Emmesomyia, Pegomyia, Anthomyia, Hylemya and Hydrophoria, have separate accounts.

But, as previously mentioned, most anthomyiids can't be reliably identified from photos and, therefore, you end up accumulating a lot of images that tend to get filed and forgotten. I've featured a small selection of those photos below for future reference. Most will have shots from other angles and, if this had been almost any other family, I think that there would probably have been sufficient detail for some level of identification. But it's not any other family, so unless I spot a feature that leads me to a particular genus, or come across a photo of a similar looking species that I can use for comparison purposes, they will remain as undetermined.  

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Updated Oct.24 (v.2)