It’s been a while since I’ve blogged about a new leaf-mining moth, and today you get two for the price of one.

You see, the larvae of both these moths mine the leaves of Alder trees, creating a blotch with a single strong crease along the mine’s centre but, fortunately for those of us trying to identify these mines, there is one vital difference: the larval mines of Phyllonorycter rajella (below) can be found on the underside of the leaf, whereas the mines of Phyllonorycter stettinensis (above) are on the upper side of the leaf.

Both moths are bivoltine, i.e. they produce two generations each year; in both cases, the adult moths are active in May and again in August, so there’s a good chance of seeing the mines right through the summer. Amazingly, I’ve actually seen the adult Phyllonorycter rajella moth several times – two instances are shown below, but you can see better images of the very pretty adult moths of both these species on the UK Moths website: click the name to see Phyllonorycter rajella here, and Phyllonorycter stettinensis here.