Wingspan 9–14 mm. A blackish-brown colored Gelechid which resembles Monochroa conspersella.

A short and broad appearance with a red abdomen and it can be found in May and June.

Initially starting as a mine along the midrib becoming a large, transparent, full-depth blotch with accumulated frass at the beginning of the mine. The mine becomes strongly folded lengthwise, causing the two halves of the leaf to more or less fold together.
When the larva is mature, it leaves the mine to pupate under a new leaf.

The larva mines the leaves of the host plant, and sometimes also feeds on spun flowers. Pupation under a leaf or in seed capsules. It is possible to find the larvae of this species together with the larva of Cnephasia asseclana which lives on the same host plant. The adults become active around sunset and later come to light.

The larva feeds on Primula veris and Primula farinosa, the latter not present in Belgium.

It occurs on calcareous grounds.