Eriocrania sangii
Eriocrania sangii, the large birch purple, is a moth of the family Eriocraniidae found in Europe and described by John Henry Wood in 1891. The moth can be found flying in sunshine around birch trees and the larvae feed on birch leaves.
Description
The wingspan is 9–14 mm. Edward Meyrick gives this description: head whitish-grey-ochreous, more or less mixed with dark fuscous. Antennae 1/2. Forewings elongate, bronzy-purple, with more or less numerous pale shining golden irregular spots: a subtriangular pale golden dorsal spot before tornus, reaching half across wing; cilia bronzy-grey, on dorsal spot ochreous-whitish; 9 absent. Hindwings bronzy-grey, towards apex purplish-tinged. Larva grey; head black, centre and mouth brown; 2 with two groups of black spots: in brownish blotch in leaves of birch. ;Similar speciesE. sangii looks similar to E. semipurpurella and can only be told apart by microscopy of the genitalia.
The moth can be found flying in sunshine, around birch trees, in March and April. In dull weather they rest on twigs.<*
;Ovum
Eggs are laid in a leaf bud of birch.
;Larvae
The grey larvae mine the leaves of birch. The mine starts as a short gallery, close to a leaf margin and develops into a large, white, full depth blotch. Frass is in long threads. The leaf mines can be found from the end of March until May and when vacated, the mine shrivels and withers away. Larvae feed on downy birch, silver birch.
;Pupa
Pupation is in the soil, within a tough silken cocoon.