Psyllobora vigintiduopunctata (Linnaeus, 1758)
A common grass and meadowlond species throughout England but less so in the north and Scotland. Adults feed on mildews from a variety of plants but are especially common on umbellifers e.g. Hogweed (Heracleum) or Angelica and, in our experience, Oak (Quercus) also. During July and August they may be found just about anywhere. Adults overwinter close to the ground in grass tussocks or under debris and occur in Berlese samples from a range of habitats. Around Watford they have been found active on the underside of Dock (Rumex spp.) throughout the winter.

3-4.5mm., although small specimens (<2.5mm) occasionally occur. Glabrous. Bright yellow with 11 or very rarely 10 well defined dark spots on each elytron, almost always discrete; fusion between spots is rare. Pronotum with 5 distinct dark marks. Head with characteristic black markings. Antennae, palpi and legs dark yellow, femora extensively darker and outer edge of tibiae black.

Description from 4 Watford specimens at X20