DIPTERA > BRACHYCERA | Higher Diptera

MUSCOMORPHA > SCHIZOPHORA > Acalypratae > Sciomyzoidea > Sciomyzidae (72 species)

(subfamilies: Phaeomyiinae, Salticellinae and Sciomyzinae)

Although the normally adopted common family name of Marsh Flies is widely used to describe these species, they are also collectively known as Snail-killing flies as most of the species have larvae that are predators or parasitoids of various snails. There are also a few sciomyzids whose larvae attack slugs or freshwater clams for example, but the majority solely feed on snails.  

Sciomyzidae is a large family of interesting, generally slender, flies where a number of species have really nicely marked wings. Defining features and preferred habitat vary from one species to another, so rather than listing general family characteristics, here’s a little bit of more specific information for the few species that I have seen, photographed and identified, all of which are in the larger Sciomyzinae subfamily.

Coremacera marginata - a fairly large and striking sciomyzid with broad wings that have numerous whitish spots on a dark membrane, a grey body with a black spotted mesonotum, red and black legs and white arista, and with the tip of the third antennal segment having a characteristic tuft of black hairs. Widespread and frequent in the south, scarcer in the north, Coremacera marginata can be found in a variety of grassland habitats, woodland rides and clearings. Adults may be seen from May to October.

Elgvia cucularia - one of two medium-sized species with a strongly curved posterior cross-vein and variably spotted wings. The grey thorax distinguishes the species from the slightly larger Elgvia solicita, which has a brown thorax. A widespread and locally common, primarily southern species that can be found in a variety of wetland habitats from April right through to September and sometimes later dependent on the weather. 

Pherbina coryleti - a large and fairly distinctive brown sciomyzid with wing spots that form a sort of loose lattice over almost the entire wing membrane. Pherbina coryleti is regarded as being one our most common sciomyzid species, found in a wide variety of swampy wetland areas from May to September.

Pherbellia dubai - a medium-large, rather slim and long-legged species with a greyish mesonotum and with the apical two-thirds of the third antennal segment black. Widespread and frequent in semi-natural broadleaved woodland, more frequently in calcareous areas, where it can be encountered from May to August.

Pherbellia ventralis - a small species with the thorax, occiput, ocellar triangle, orbital plates and front legs blue-grey, contrasting with a yellowish or brownish abdomen. The antennae and majority of the frons are orange. It’s fairly common over much of the country, occurring in wetland areas such as marshes, water margins, and wet heath, but also found in grassland and occasionally in gardens. Adults can usually be seen from April to October, but are most frequent in spring, albeit the one I saw in our garden was in February.

Renocera pallida - a small tawny-brown, rather shiny species with the apical half of the third antennal segments conspicuous darkened and clouded cross veins. Males have a rather large reddish genital capsule. 

Tetanocera ferruginea - a common wetland species that is usually active from May until September. It is regarded as being the typical Tetanocera with distinguishing features that are useful for comparison with, and identification of, five or six closely related species.

Tetanocera fuscinervis - (no longer featured as deemed incorrect) a small, rather plain species with a slightly shining frons lacking any median stripe and with only a vaguely striped thorax. A widespread, but localised species that is known to favour base-poor wetlands, such as valley mire and raised bog areas.

Trypetoptera punctulata - a distinctive, locally common species, which may be found in a variety of habitats from woodland clearings and rides to grasslands and heathland. At first sight it could easily be mistaken for a picture-winged tephritid fly until you take a closer look at the face and antennae.

Updated Nov.24 (v.4)