Fenusa pumila

    Description

    Adults: Small black sawflies 3.7 mm long. All black except for small amounts of white on each femur, tibia and tarsus. Wings with light brown banding and darker near the body. Antennae shorter than thorax (longer in Fenusa dohrnii). The larvae mine the leaves of Birch producing a blotch on the upper side of the leaf. It starts by the midrib and extends towards the leaf edge. The larvae have four spots - the anterior spots (those near the head on the underside) being large (as shown) which distinguishes it from P.thomsoni.

    Identification difficulty
    Habitat

    Where Birch is present.

    When to see it

    The larval mines can be seen when Birch is in leaf.

    UK Status

    Status in Britain is difficult to determine due to lack of records.

    VC55 Status

    Rare or under recorded in Leicestershire and Rutland.  The Fosse Meadows record of 3rd October 2018 is thought to be the first for VC55.

    Leicestershire & Rutland Map

    UK Map