Eriocrania sangii, the large birch purple,[1] is a moth of the family Eriocraniidae found in Europe and described by John Henry Wood in 1891.

[4] The moth can be found flying in sunshine, around birch trees, in March and April.

In dull weather they rest on twigs.<[5]* Eggs are laid in a leaf bud of birch.

The mine starts as a short gallery, close to a leaf margin and develops into a large, white, full depth blotch.

The genus Micropteryx was raised by the German entomologist, Jacob Hübner in 1825 and comes from the Greek for mikros, little and pterux, a wing.