|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
of this resemblance.