unknown insect

unknown insect

Observation - unknown insect - UK and Ireland. Description: taking nectar from Black Horehound. Only settling briefly. Two insects, the one pictured and I think the same but larger (a male) patrolling a patch of this plant, Maybe its territory?

taking nectar from Black Horehound. Only settling briefly. Two insects, the one pictured and I think the same but larger (a male) patrolling a patch of this plant, Maybe its territory?