Last modified: June 6, 2020, 12:38 p.m.
A very rare species in Belgium, nowadays mainly distributed in the northern part.
The colour of the fore wings is variable: yellowish, ochreous till brownish. The lighter lines are obscure and there are most of the time dark stipples in between, especially at the base of the fore wings. The antennae are ringed alternately the first half. Wingspan is 10,5–15 mm.
The case is greyish and 7–8 mm. It is made of silk. The case is somewhat swollen in the middle and has darker length lines. The mouth angle is 10°–50°.
See also bladmineerders.be.
At first the caterpillar, appearing in May, is living in a seed till it is about 1 mm. Then it makes a silken case on upon wich frass and plant rests and other things are hanging. Finally the caterpillar disconnect itself from the seed and goes eating other seeds. Fully developed the case is greyish and 7–8 mm. The caterpillars overwinter in the case.
The adults fly from the end June till the end of September.