DIPTERA > BRACHYCERA | Higher Diptera

LOWER BRACHYCERA > TABANOMORPHA > Tabanoidea > Tabanidae (30 species)

(subfamilies: Chrysopsinae and Tabaninae)

The various members of this family as a whole can be described as typically squat, robust flies, mostly with strikingly coloured eyes with iridescent or metallic bands across them. A few species are supposedly easy to find in the countryside around paddocks and stables as their common name suggests, while others may only be found in a specific habitat, such as natural wetlands, saltmarsh or base-poor mire and bog.

As with all the main family groups within the Lower Brachycera they have been given individual common names but, although most species are loosely designated as horseflies, the four British representatives of the Chrysops genus are officially known as deerflies, and the five Haematopota species as clegs. You'd therefore assume that the Chrysops species are associated with deer, but that's not actually the case as deerflies is the collective name used in North America that we've simply maintained for consistency. The term cleg is even more obscure as there doesn't appear to be any truly known meaning other than it may have come from the old Norse word kleggi, which roughly translates 'to stick', as in the insect latches on and is difficult to shake off.

It's common knowledge that only the females bite and, in theory, only do so after mating when they need blood for their eggs to develop. The main culprits are the larger Tabanus species, which usually target horses and cattle. The nasty ones are the clegs, notably Haematopota pluvialis, which are annoying and persistent species that are often encountered in damp woodland during the summer. They happily and readily bite humans, as I can vouch for, even through quite thick clothing. The individual featured below was photographed on my bag, whilst her mates were enjoying themselves biting any bit of me where they thought they couldn't be seen. In that respect, they particularly seem to like the back of your legs! I wouldn't actually mind suffering the pain now and again, if the blighters would settle on foliage so I could get a few photos, but they never do.

General family characters are given as medium to very large (6-30mm), stout flies, devoid of bristles; body generally brown, black or grey and with a pattern of lighter markings, although in some cases yellowish, greenish or metallic blue; eyes often brilliantly reddish or metallic green, sometimes yellowish, and often with spots or bands; male eyes holoptic, female dichoptic; antenna with 6 or more segments, usually with a large third segment and tapering style; in most females the mouthparts constitute a powerful, often long piercing proboscis; wings variable, but with the costa surrounding the whole margin; veins R4 and R5 form a wide fork spanning the apex; lower calypters conspicuously large; legs powerful; tibia of mid leg and in some cases hind leg with apical spurs.

For various reasons, my encounters with horseflies in general, other than Haematopota pluvialis and the common Tabanus bromius, is awful, even though parts of East Dorset and the New Forest are recognised as being the richest areas in Britain for finding them. In fact, it's quite embarrassing to see that at present, apart from those two previous species, I can only represent the family with a single shot of the saltmarsh horsefly Atylotus latistriatus when it momentarily landed in front of me, a chance in-flight photo of the distinctive wetland species Hybomitra distinquenda that had been hovering over a footpath, and a couple of 'staged' photos taken in the garden of the giant horsefly Tabanus sudeticus that had somehow found its way into our kitchen.

The situation with soldierflies is much the same, so I can only assume that it's mainly due to habitat and that if I want to add more species, I will need to find some different locations. Although many of my fly sightings are from chance encounters, I've also had quite a bit of success when targeting specific species which only occur in certain habitats, and I suspect that I need to have a similar approach here.

Updated, Dec.24 (v.2)