The lower epidermis seems smooth, but has many fine length folds.

These can appear on the upper and lower epidermis of the leaves.

The lower epidermis has several long folds which are positioned close together.

The lower epidermis has a single sharp fold, which is sometimes forked near the end.

It has a number of fine folds in the lower epidermis.

The lower epidermis has one or more strong folds.

The lower epidermis of the mining part is finely wrinkled.

There are no clear folds in the lower epidermis.

After hatching they mine in the lower epidermis of the leaf.

The lower epidermis has many weak wrinkles but no clear folds.