One of the first things you realise when you start looking at Diptera is that it’s all about hairs. Or in some cases bristles, that are just stiff hairs, or spines, which are I suppose are a bit stiffer still. Dipterists are obsessed with hairs, and if the hair has been broken off they will go in search of the hole that it grew from. Diptera have something for everyone and if you’re not into hairs then there are families in which they’re not so important, such as the hoverflies and the cranefly families (Nematocera). As flies evolved from the earliest forms (Craneflies are considered the most primitive) they gradually lost wing veins and gained hairs, the “hairy flies” like Muscidae and Calliphoridae being considered the most recent to evolve.
Tom provided us with plenty of specimens (which was fortunate because there aren’t many flies about in December) and we were soon working through the keys, which are available online from the Dipterists Forum. Mostly the keys are easy to work with although there are a few sticky parts – many of us had trouble working out how to find hypopleural bristles! Dipterists forum have a lot of draft keys, of which Tom had copies, and the RES publish quite a few more, some of which are free online, so many families are very accessible. If you have started with hoverflies, then craneflies, Muscidae, Calliphoridae, Tabanidae, all have keys and are fairly large species. Some flies are awfully small though! We saw some specimens of Ceratopogonidae which were small even under a microscope and need specialist study.
Many thanks to Tom for spending another day with us, and to Paul Quigley and Norton Priory for providing the venue and refreshments.