DIPTERA > BRACHYCERA | Higher Diptera

EREMONEURA > Empidoidea > Empididae (207 species)

(subfamilies: Clinocerinae, Empidinae and Hemerodromiinae, sometimes Oreogetoninae and Trichopezinae)

Although the common name of 'dance-flies' is still occasionally used for members of this family, it was effectively adopted by the Hybotidae (also Atelestidae and Brachystomatidae) when those species were separated. The more current name is dagger flies, referring to the sharp piercing mouthparts of some species.

Empids (or empidids) can be found in a range of habitats including open woodland, grassland, meadow edges, alongside streams and rivers, and other wetland areas. Most species are predatory, but some are forage on tree trunks and others visit flowers for pollen and nectar. Typically though, they’re more likely to be seen sitting on vegetation waiting for suitable prey in a very similar manner to robberflies. They can actually be confused with the Asilidae as there is a superficial resemblance.

General characters for the family are given as minute to large (1-12mm, sometimes bigger) flies; body is slender or elongated, rarely thickset; colour can range pallid to dark, sometimes lustrous, but not metallic; head small, but with relatively large eyes, in some cases holoptic and often with an incision at level of antennae; several genera have powerful and piecing mouthparts, some elongate projecting forward or downward; antenna usually with three segments of which the third is the largest and bears a short or long, usually arista or style; wings clear or partially tinged, in some cases with a stigma spot or distinct wing pattern; legs powerful, usually long and slender, in some cases the forelegs are raptorial, adapted to catching and holding on to prey; radial vein R4+5 is often forked and the discal-medial cell (dm) is almost always present; the costa ends at or just beyond R4+5, or continues along the wing margin, and can be used as a characteristic to distinguish Empididae from other families.

The most frequently observed empids are Empis livida and Empis tessalata; the former being the most common and widespread species in the genus, and the latter being the largest and one of the easiest to recognise. Empis lutea is a distinctive species due to its bright orange colour but, for whatever reason, is nowhere near as well recorded nationally although, strangely in Dorset, it has more records than Empis tessalata. Yet, with Empis trigramma, which is reasonably common across most central areas, there are very few records from the south and not one from Dorset. And, when I look at Empis pennipes, which is another species featured here where the identity has been confirmed, I find that the last record from Dorset was back in 1998. The last new species added to the page, is the tiny Empis albinervis that had conveniently landed on the back of my hand. It's not that common nationwide, but is well recorded in Dorset.

Hilara maura is another well-known member of the family but, with over sixty species in the genus, they are not easy to identify and, even though the individual below is pretty much certain, it's best left as 'likely' as the specimen wasn't properly examined.

Updated Nov.24 (v.3)