DIPTERA > BRACHYCERA | Higher Diptera

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

(subfamilies: Anthomyiinae and Pegomyiinae)

The Hylemya genus includes four species, with Hylemya vagans and Hylemya variata being two of the most frequently seen and recorded flies in the Anthomyiidae. Far less common are Hylemya nigrimana and Hylemya urbica. Whilst the males can generally be distinguished by the colour of their legs, the females are usually recorded as a pair as they cannot be separated unless seen or collected with males - except that you can often find more than one species in the same area, so it's best to accept that females can't be identified.  

They are medium-sized flies with a body length of around 7-9mm, although with Hylemya variata some individuals may be as small as 4mm; slim with more or less cylindrical abdomen; brownish-grey with a somewhat variable dark median stripe on the thorax and two rows of black spots at the insertion points of the dorsocentrals, also dark lateral blotchy markings that contrast with the pale humeri and notopleuri, giving the effect of a broad pale band running across the side of the thorax; the abdomen also has a dark median stripe and dark bands may also be present across the base of tergites 3-5; the legs vary from partially brownish-yellow to all-black (as detailed below); the eyes are bare, with the narrow white orbits touching in the males; the arista are long and plumose with well-spaced rays.

Distinguishing males via their leg colour:

Hylemya vagans - femora black (dark); tibia mostly yellow to brownish- or reddish-yellow,

Hylemya variata - femora and tibia black (dark), although the tibia is sometimes obscurely reddish,

Hylemya nigrimana - front femora black (dark); mid and hind femora, and tibia, yellow to brownish- or reddish-yellow.

The females cannot be separated in the same way so are best recorded as pairs:

Hylema vagans / nigrimana - mid and hind femora yellow to brownish- or reddish-yellow,

Hylemya variata / urbica - femora black (dark), at most knees lightened.

From general appearance Hylemya variata and Hylemya urbica are the smaller, 4-7mm BL species. They are very similar and strictly speaking, the male genitalia needs to be examined but, for personal records, check the eyes, as the narrow white orbits are touching or at least very nearly touching in Hylemya variata, whereas in the far less common Hylemya urbica they are narrowly separated. Hylemya variata can be found in a variety of habitats and is much less attached to woodlands than the following species.

Hylemya vagans and Hylemya nigrimana average a tad larger, closer to 9mm. Hylemya vagans is typically darker and more strongly marked than Hylemya nigrimana, which generally has a paler, greyer body. Both of these species have a strong association with woodlands, the latter particularly favouring damp woodland.

Hylemyza partita (not yet featured) is the only member of this closely related genus (note the spelling), duly referenced here as it appears in the same identification key as Hylemya. It's a small, generally dark-coloured species with two rows of acrostichal setae which are more widely spaced than in the Hylemya species and, at least present in front of the suture, two further rows of fine setulae. Another more visual identifying feature is that the scutellum has a small bare triangle at the base.

The three species within the Hydrophoria genus are superficially similar to Hylemya, but differ by having a larger lower calypter. I was going to incorporate these two genera together but, looking ahead, I've moved the genus to the next page to maintain space and avoid confusion.

Hopefully I will be able to feature some photos here of Hylemya nigrimana at some point and, being optimistic, possibly Hylemya urbica, but in the meantime the page will be routinely updated in order to add further and/or better representative photos. 

Please use the 'previous page' (<) button above to cycle back to the introduction,

or the forward 'next page' (>) button to move on to Hydrophoria

New page, Oct.24 (v.1)