Balloon Fly - Hilara maura

3-4.5mm. Dark grey with few bristles on the thorax and legs. Males have distinctly dilated front tarsi which lack the long hairs seen in some other species. The thorax has three indistinct dark stripes which appear as one broad black stripe when viewed from behind. with thorax very distinctly grey on each side of it.

There are around 60 British species in this genus and identification is difficult, for this reason images placed in red boxes can only be said to be representative of Hilara maura.

Males

• 3-4.5mm. 
• distinctly dilated front tarsi which lack the long hairs
• dark grey with few bristles on the thorax and legs. 
• thorax with three indistinct dark stripes which appear as one broad black stripe when viewed from behind
• haltere dark
• hind femora dilated but not abruptly narrower at tip
• dorsocentrals bi- to triserial but very short and hair-like

A specimen must be keyed, it isn't possible to confirm the species from a general image.

Can be seen swarming over water and marshy areas in the summer months.

Best from May to July.

In the insect world males often present the females with a prenuptial gift of food, usually a small fly, but the males of the Hilara spp. go one step further and gift wrap the present in silk that is exuded from the swollen glands on their front legs. While the female is pre-occupied with unwrapping her present, the male takes the opportunity to mate.

They are common throughout Britain.

Status in Leicestershire and Rutland not known but probably fairly frequent.