|Adults feed on flowers, especially those of
carrot and fennel.
10 - 12 mm.
The larva of E. tenax lives in drainage ditches,
pools around manure piles, sewage, and similar
places containing water badly polluted with
organic matter. The larva likely feeds on the
abundant bacteria living in these places.
March onwards. However, the adults hibernate
in the winter, and they can therefore also be seen
on mild days in January and February.
The adult fly that emerges from the pupa is
harmless. It looks somewhat like a drone
honey bee, and likely gains some degree of
protection from this resemblance to a stinging
insect. The adults are called drone flies because
of this resemblance.