Alosterna tabacicolor (De Geer, 1775)
Although occuring widely throughout England and Wales the distribution of this species is patchy; most records are from the south and they become sparse further north to Cumberland and Northumberland although the species seems to be absent from Lancashire and north Yorkshire. There is a single record from southwest Scotland (Twinn and Harding). While Joy describes the species as local from England and southern Scotland, Hickin quotes it as rare but this is not our experience locally; from each year of our recording (2003-2008) Alosterna has been common throught our area, in woodland and wooded pasture they are usually abundant and this is also the case further south through Rickmansworth, Harefield, Denham and Uxbridge. Depending on season adults appear towards the end of April when they are most easily observed on, or flying around, the flowers of Ranunculus spp. (Buttercups), at this time the flowers of Rosa are also productive and beating Crataegus almost always produces the species. Numbers increase and soon they are found on flowers in any suitable habitat but perhaps the greatest abundance is to be found during June on umbels (etc) alongside the pathways through Whippendell wood. Bily and Mehl quote the adults visiting flowers 'especially those growing in the shade' but in our experience the opposite seems to be the case.

Alosterna is easily recognised in the field but care must be taken to distinguish the species from the superficially similar Pseudovadonia.

6-9.5mm. An elongate and slender species. Head black, obliquely produced forward to longitudinal axis of body, densely punctured and with sparse pale recumbent pubescence. Eyes longitudinal, curved above around antennal insertions. Temples short and angulate, strongly contracted at base. Antennae black with basal segment lighter, covered with dense golden pubescence, reaching elytral apex in female, shorter in male. Second segment as long as first and longer than third. Palps testaceous. Pronotum elongate and convex, broadest in front of middle, sides smoothly sinuate and without borders. Front angles rounded, hind angles obliquely produced backwards. Entire surface densely punctured and with backwardly recumbent yellow pubescence. Scutellum black. Elytra testaceous with side margins, suture and apical area darker. Almost parallel; a little broader behind prominent shoulders. Suture slightly raised otherwise without striae or ridges, each separately rounded at apex. Entirely punctate, much less densely so than pronotum, and with long, backwardly recumbent yellow pubescence. Legs long and slender, testaceous with tarsi variously darker. Mid and Hind femora distinctly broadest towards apex.

Description taken from 2 Watford specimens examined at X20