Phyllobius virideaeris (Laicharting, 1781)
A common and widespread weevil occuring throughout England and Wales and with scattered records across southern Scotland (Morris). The species is abundant throughout our area in just about any habitat that includes unmaintained grassland, large numbers may be swept from open grassland but when this borders trees and shrubs they will occur on a wide range of species eg during June 2008 they were abundant among grass throughout Cassiobury park but were also swept in large numbers from Hawthorn hedges and overhanging Oak, nettlebeds, riverside herbage and the great variety of garden plants along the northern boundary. They are common throughout our local woodlands and along unkempt road verges. An area of notable abundance is the open grass scrub on the eastern (dry) side of Common moor where, from late May to July adults may be taken by the hundred from a few metres of sweeping. Adults begin to emerge in late April when they occasionally occur in grass and herbage sweepings but the first sign of abundance is from beating freshly flowered Crataegus around the beginning of May, from this time they increase in abundance and by mid-May are common everywhere and remain so into July or August. Although the species is polyphagous it is not, or perhaps only adventitiously, arboreal. The larvae are subterranean, feeding on a range of herbaceous roots.

The equally widespread and very similar P.roboretanus Gredler often occurs with virideaeris, the best field character is the scaling beneath the abdomen in virideaeris; the upperside characters are very subtle under field conditions. During 2006-2008 by far the most abundant species locally has been virideaeris.

3.7-5mm. Elongate, upper surface entirely covered with brilliant, metallic round scales although occasional specimens appear dull, usually a mixture of green, blue and golden yellow, most specimens specimens appear predominantly green or yellowish green but vivid blue specimens are not uncommon (at least locally). Head broadest at eyes, temples parallel or nearly so, vertex convex becoming flat between eyes. Rostrum broad, slightly transverse, scrobes and antennal insertions distinct from above, scrobes run to front margin of eyes but are generally filled with scales and so obscure. Antennae testaceous, scape distinctly angled, funiculus 7 segmented, 1 and 2 elongate, 3-7 quadrate and club 3 segmented, elongate and pointed. Pronotum transverse (about 5:4), sides rounded and broadest at middle, without borders. Front margin weakly raised. Elytra with prominent shoulders, almost parallel to widened and broadest behind middle. From an examination of many specimens elytral shape seems to bear no relation to sex. With 10 well impressed and punctate striae, these are for the most part devoid of scales and obvious. Sutural striae widen from before scutellum to base ie may run parallel to scutellum, this is variable but some degree of widening is usually obvious. All interstices with fine, pointed and semi-erect scale like setae. Apical declivity oblique. Underside of abdomen densely scaled, terminal sternite with a depression in female. Legs testaceous, femora variously darker and usually with some metallic scaling. Femora not toothed underneath. Apex of protibiae evenly rounded.

Description from 6 Watford specimens at X30

See ID Aids for a separation of P.virideaeris and P.roboretanus