Macan, T.T., 1961
A Key to the Nymphs of the British Species of Ephemeroptera
Dichotomous key to species with a line or two of notes on each. There follows a short chapter on life-histories with phenology diagrams and then vice county distribution maps
||Freshwater Biological Association (FBA)
||All the then known British species.
||Line drawings accomanpy text, vice county maps at the back.
||Under a Stereo Microscope.
||Live specimens often have distinctive gis, but they may need to be killed for detailed examination of mouth parts or gill lamellae.
||Most of the difficulties lie in dissecting these fragile, pale coloured and often small insects.