This species was described scientifically in 1835 by English entomologist James Francis Stephens (1792 - 1852), who gave it the binomial name Paraleptophlebia submarginata.
The Turkey Brown is found most often on spate rivers and rain-fed streams in southern and western Britain, but it is less common in southern Scotland and not reported from northern Scotland. This mayfly is also rarely seen on the chalk rivers of southern England. The nymphs are poor swimmers, crawling among mosses and tunneling within waterlogged leaves, particularly in the slower moving water of river margins..
The dun hatches throughout the day from April until July. May is usually the month of peak emergence, but these mayflies are rarely plentiful. The nymphs crawl up stems or onto emergent woody debris, and hence most of the emerging duns are not available to trout unless blustery winds blow them onto the urface of the stream.. A Turkey Brown spinners lays her eggs during the day and early evening, depositing abojut 1000 eggs in one batch by dipping her abdomen into the water as she flies upstream. Spent females fall to the water surface and are available to feeding trout..
An artificial March Brown is an adequate imitation for this swarthy three-tailed mayfly, but on turbulent water I find that a general purpose fly such as Greenwell's Glory does the job more than adequately.