Paul Leyland – Empis tessellata
Paul writes: Empis tessellata is a common fly and can be seen throughout the UK, it belongs to the family Empidae, also known as Dagger Flies. The family is quite distinctive, typically with a small head combined with long body and legs. There are several similar species, Empis tessellata can be told from its black thighs. I usually see them in July and August, when they can be abundant, feeding on Umbellifers, particularly Hogweed. It is quite a large fly, about 10mm long.
The dagger is the long downward pointing proboscis. This is used for probing among flowers to feed on the nectar and also spearing prey, generally other fly species. The Dagger Fly has an interesting mating ritual. The male will kill a fly and take it to a waiting female as a gift. She can then decide to accept and if she does will devour it whilst being mated.