DIPTERA > BRACHYCERA | Higher Diptera

LOWER BRACHYCERA > TABANOMORPHA > Tabanoidea > Rhagionidae (15 species)

(subfamilies: Chrysopilinae, Rhagioninae and Spaniinae)

It’s useful to note that the long-established common name for this family doesn’t actually provide any meaningful clues regarding either the appearance or habits of the species, as both the origin and significance of the term 'snipeflies' is unknown. The best guess is that 'snipe' may relate to the freshwater shorebird of that name, which is primarily a wetland or marsh species just like many members of the Rhagionidae family.

Snipeflies have considerable size variation with several species being large and conspicuous while others are very small and unlikely to be seen unless you’re specifically looking for them. The most distinctive, and probably the most common, snipeflies are in the genus Rhagio of which there are six species. They are the larger members of the family with a yellow, black-marked, typically conically-pointed abdomen and, when found resting on vegetation, have their long wings swept-back and their head facing downwards. The medium-sized Chrysopilus species are much more delicately built and have long slender legs.

General characters for the family are given as small to large (2-20mm) flies with long wings, legs and abdomen; body and legs mostly without bristles or only partially pubescent; body colour yellow, yellowish brown or black, often with a brownish, grey or dark pattern; male eyes are generally holoptic; third antennal segment swollen and with a dorsal or terminal style or arista; mouthparts usually fleshy; wings usually clear and often with a dark stigma spot, in some cases mottled; veins R1 and R2+3 well separated at the wing margin. The anal cell is useful for separating Rhagio from Chrysopilus, being open in Rhagio, but closed in Chrysopilus.

Chrysopilus asiliformis - a small, 5-6mm long, species with conspicuous bright yellow hairs on the thorax and abdomen when fresh, otherwise more greyish-yellow. Males have a slender, banded abdomen with the tergites having a dark anterior fringe. The females have a chunkier and more uniform greyish appearance. The eyes are bright green, the legs are long and the wings usually have a dark stigma although often faded.

Chrysopilus cristatus - a medium-sized, 6-8mm long, dark-coloured species. The males are mostly blackish-brown, whereas the females are paler, more yellowish-grey depending on the angle of view. The top of the thorax has stripes, which are more obvious in the female and the femora are mainly black. As with other members of the genus, the male has a much more slender abdomen than the female.

Rhagio lineola - the smallest member of the genus with a body length of around 6-8mm. The thorax is plain grey- dusted and the wing stigma is strongly darkened. The front and mid femora are normally yellow with a dark pre-apical ring, although very occasionally individuals might be found in which both the abdomen and the legs may be darkened.

Rhagio scolopaceus - a medium to large, 8-16mm body length, species with a grey thorax and distinctive mottled wings with a dark stigma. The abdomen has long hairs on the sides and the tiny third antennal segment is pointed, being a specific feature to rule out any possibility of the rarer Rhagio strigosus.

Rhagio tringarius - a medium to relatively large, 8-13mm long, rather variable species with a dull greenish-grey thorax and an orangey-yellow coloured abdomen that typically has a number of dark black spots on the dorsal surface that often end up as bands on the final segments which, in some individuals, may be far more extensive. The main distinctive feature of the species is that the wings are clear with a yellow rather than dark stigma.

It's taken me a good couple of years since my first sighting of these flies to add a further species to the list. I seem to regularly find the other four but, for whatever reason, Rhagio lineola has previously eluded me even though it's one of the most frequently recorded snipeflies. The challenge now is to find one of the other, much rarer species, as the five currently featured here account for just over 90% of all Rhagionidae records on the NBN Atlas database at the time of updating the page. That's quite incredible when you realise that there are ten further species that could be encountered. Having looked at the local records for both Dorset (VC9) and South Hampshire (VC11) I think it's probably unlikely as there have been virtually no confirmed sightings of any other species over the past twenty or so years. From historical records, the most likely two are probably Ptiolina obscura, which is a tiny dark-coloured woodland species that seems to be associated with moss; the other, Symphoromyia immaculata, is a small, rather drab, greyish fly, which could possibly be found locally on somewhere like Martin Down as its primary habitat is dry calcareous grassland.

Updated, Dec.24 (v.3)