. . . Reaches Those Parts That Other . . .

It is said that this fly can reach those parts that other flies cannot reach.
Consequently, it is sometines called the Heineken Fly.

Officially, it is Rhingia campestris aka Black-rimmed Snout Fly

The snout is a sheath for storing the folded proboscis when not feeding.
Here it is feeding from red campion, Silene dioica