Semaphore flies

After a wildlife-packed June with the 30 days wild challenge, I felt like I needed a new focus and I decided to carry on a wildlife challenge by blogging/tweeting about an invertebrate I've seen that day for July. Yesterday, while walking by the local park pond I saw a Speckled Wood. The butterfly flew away, but it made me notice the flies dancing on the Colt's Foot leaves: they were Semaphore Flies, Poecilobothrus nobilitatus, a whole swarm of them signalling to each other. Although small, this species is very easy to identify by their smoky wings with a white tip. They are very active in July on muddy puddles and ponds.