|Olibrus corticalis (Panzer, 1796)|
|Apparently widely distributed across southern England and Wales; there are
modern records below a line from Pembrokeshire (coastal) to Leicester and the Wash but seemingly absent from the
west country (NBN, April 2009). Thompson also
gives records from the Isle of Wight and (unverified) Northumberland. A common species throughout our Watford
area; we have recorded them during hot weather on a variety of flowers eg. Taraxacum (Dandelion),
Tussilago (Coltsfoot), Tanacetum (Tansy) and others, mostly when these are growing in unkept areas
of grass eg Cassiobury park or Radlett road and also in town centre gardens. During 2007 we recorded them at MV
each month from May to September in a town garden where the lawn had been allowed to grow and host an abundance
of Taraxacum, Senecio vulgare (Groundsel) and Hypocharis radicata (Common cats ear). In
anything other than hot and bright sunshine the beetles tend to remain hidden deep within flowers, we find the
best way to observe them is to shake the flowers vigourously into a clear plastic bag.
A small but distinctly coloured species, dark in front with pale elytra and very shiny, after a while they become obvious in the field with a X10 lens but specimens will need to be examined closely to be sure of the identification.
2.5-2.9mm (Thomson) Head and pronotum dark brown, the head in most of our specimens is darker. Elytra pale brown with suture, lateral margins and areas around scutellum (a triangular mark) and shoulders darker. Head, pronotum and elytra microsculptured, this can be difficult to see; examine at X100 or more in strong diffuse light and take time to slowly move the focus above and below the cuticle, after a while the sculpture becomes obvious. Sometimes the sculpture is very weak on the head and pronotum, in our experience it is best looked at behind the eyes and towards the base of the pronotum. Head broadly transverse and weakly produced in front of eyes, eyes continuous with outline and forming the lateral angle, surface finely punctate. Antennae pale yellow, inserted under front margin before eyes. Terminal segment constricted in apical third. Palps entirely pale. Pronotum finely bordered anteriorly and laterally, front angles produced and perpendicular, hind angles slightly obtuse. Surface finely punctured, dark brown but often lighter towards margins. Elytra with longitudinal lines of fine punctures, between these are scattered very fine punctures (X60). With two well impressed striae from apex (or very near) to at least the basal third and often very close to basal margin. Sutural striae usually continued to inside the apical angle wher they meet, the outer striae generally end just before the apex, or unite with the sutural striae very near the apex, or end subapically but continue as a few punctures which unite with the sutural striae. Legs, including claws, yellow. Tarsi 5-5-5; basal segment appears quadrate, 2 and 3 bilobed, 4 tiny and not usually visible, 5 long and gradually widened to apex. Claws appendiculate.
Description from 3 Watford specimens X60 and X100