Muscidae

Houseflies (6)

DIPTERA > BRACHYCERA | Higher Diptera

MUSCOMORPHA > SCHIZOPHORA > Calyptratae > Muscoidea > Muscidae (293 species)

(subfamily: Phaoniinae)

Phaoniinae (91)

Putting aside Atherigona where there is only a single record, and also the two very infrequently seen Lophoscelesspecies that despite being described as widely distributed, have as far as I know, never been recorded locally, this subfamily and tribe also includes the two largest muscid genera:

Phaoniini - Helina (40) and Phaonia (48)

Helina

Apart from seeking help from experts on the UK Diptera FB group I rely heavily on the information that Steven Falk provides on his Flickr photostream but, unfortunately, despite his knowledge of all these muscid species, his Helina album is still under construction. There is very little alternative detail on the internet that I can find other than Mike Hackston's keys, so I'm very wary of this genus particularly as there are so many species. The most frequently recorded species are Helina evecta, Helina reversio and Helina impuncta. Confirmed sightings for any of the other species tails off considerably although Helina depuncta is starting to be recorded nearly as often as the similar Helina impuncta whereas it was quite scarce in many areas fifty odd years ago. Local records from Dorset (VC9) are poor with only Helina reversio reaching double figures. The situation in South Hampshire (VC11) is much the same.

Helina evecta has a grey dusted thorax with bluish-grey to pale brown abdomen with dark markings, four postsutural dorsocentral bristles, fine dark hairs on the lateral margins of the scutellum, hairy eyes, dark legs and wings with infuscated cross veins.

Helina reversio (not featured) is a somewhat variable species that typically has an overall beige or greyish appearance. The males tend to be darker, and the female usually has two pairs of conspicuous spots on the intermediate tergites. The legs are generally black although the middle and hind tibia and the apices of the femora are sometimes reddish.

Helina impuncta - a grey/brown species with fine, sometimes almost imperceptible, stripes on the thorax and no patterning on the abdomen; 1+2 sternopleurals; orangey-red femora and tibia, but dark tarsi; tinted wings and darkened cross-veins.

Helina depuncta - very similar to Helina impuncta, and often difficult to separate from photos. I had previously noted that Helina depuncta could be distinguished by having three, rather than four, pairs of postsutural dorsocentral bristles, but I've now been advised that while Helina impuncta normally has three pairs, sometimes it has four or even three one side and four the other, so trying to determine the species purely on the number of postsuturals isn't foolproof. However, Helina depuncta does not have any presutural acrosticals, whereas Helina impuncta usually has some. So, in conclusion, if there are three pairs of postsutural dorsocentrals in addition to the two presutural pairs, and no presutural acrosticals then the individual in question should be Helina depuncta. If there are four pairs of postsutural dorsocentrals then it can't be Helina depuncta.