Helophilus spp hover flies

To identify flies to family level use a simple wing venation key such as A Key to the Families of British Diptera, an AIDGAP by D. Unwin, published by the FSC and available as a free download (scroll down to the titles list) or a more detailed key which includes many physical characters such as The European Families of the Diptera by P. Oosterbroek. The expert dipterists on the DipteraInfo forum are also very happy to identify, often to species level, from good photographs.

The Helophilus genus of hover flies are closely related to drone flies Eristalis spp and have the same distinctive loop in the main wing vein. However, Helophilus have a striped thorax and bright yellow and black abdomen, which makes them easy to distinguish from drone flies. There are only 3 species of Helophilus which occur in France, but they are very similar in appearance. There are a few other related hover flies that have striped thoraxes, but except for Mesembrius peregrinus they are smaller and not so brightly coloured.

Striped Hover Fly Helophilus pendulus: The easiest way to tell this species from the other two is by the extent of yellow on the hind tibia, which should be more than half, from the knee down (other species have more black). It has a black stripe on the face. It is the most common and widespread species you will encounter here. The larvae live in wet manure, farmyard drains and sawdust. Adults sometimes occur together in numbers, either by ditches, puddles and pond margins, or in sunny spots with bushes and flowers. It often sits on leaves and makes a buzzing sound. Adults are active from April to November and most likely to be seen June - August.
A Striped Hover Fly, resting on an Ivy Hedera helix leaf. Note that only the basal third (the ankle end) of the hind tibia is black.

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