Less helpfully known as the southern migrant hawker, these are now well established in southern England. Each year I visit the same ditch to see how they are doing, and was pleased to find around 50 males this time (down from over a hundred last year though) - but only 2 females, one in tandem with a male egg-laying and one in a mating wheel. According to four other people I encountered they had seen no females at all, so I counted myself lucky - why so few, I do not know.