Stenocorus meridianus (Linnaeus, 1758)
Quoted by Joy as local throughout England. The latest distribution map (Twinn and Harding) shows frequent modern records throughout the south below a line from thw Wash to the mid-Welsh coast, further north records are less frequent and more scattered, mostly from the eastern half of England north to Durham. Older (pre-1970) records show a generally wider distribution. Although we have not (yet) recorded the species from our Watford area we should probably expect it; during June 2006 a specimen was recorded from an area of mature mixed broadleaf woodland near Denham (Just within Greater London) some 10km to the south of Watford. This ,presumably, is from a long established colony; we recorded the species at the same locality during 1975 and 1977 and a further record is given by Rix (2000). Although a local species experience has shown that it may be common where found. Adults occur from May until August and are easiest recorded by looking on umbel (Apiaceae) flowerheads, we have also seen them on Rubus flowers, during periods of hot sunshine they fly readily and may be observed flying from flower to flower; they fly slowly with the elytra held out and look quite spectacular. Once seen the large adults are very distinctive and cannot be mistaken for any other species.

Hickin quotes Prunus cerasus, Fraxinus and Salix as hosts and Duffy (1953) recorded oviposition on stumps of Quercus, Pinus, Fagus, Populus, Alnus, Pyrus and Betula with Populus nigra seeming to be preferred. Larvae develop over two years in stumps and underground roots, preferring those with a diameter between 0.5mm and 2cm (Bily and Mehl). Mature larvae pupate in an earthen cell alongside the roots. Palm (1960) reports two or even several years for development.

A large, 15-24mm (Duffy), and unmistakable longhorn, elongate with strongly tapering elytra in male, more parallel sided in female. Head and thorax black, elytra black or brown or a combination of these. Entire upper surface with fine golden pubescence. Head finely punctate and rugose, longitudinally depressed between eyes and produced anteriorly beyond antennal insertions. Eyes convex and protruding; round but for a shallow incision in front of antennal insertions. Temples long and evenly narrowed to base. Antennae long, reaching beyond middle of elytra, third segment much longer than first. Pronotum elongate, without side margins but with a large and blunt lateral tubercle. Transversely constricted below anterior margin, disc with longitudinal furrow, raised either side and transversely depressed in front of base. Hand angles perpendicular, hind margin sinuate and generally hidden by pubescence. Elytra dorsally flattened anteriorly becoming convex towards obliquely truncate apices, transversely rugose with larger punctures which are random but may tend to form rows (view from apex) and much finer and dense puncturation throughout (X20). Pubescence recumbent, posteriorly oblique from suture. Manipulated in strong light there are traces of two longitudinal ridges, one near the suture and one near the side margin. Legs very long and slender, mostly testaceous or dark testaceous with apices of femora, tibia and entire tarsi black. Basal and terminal segment of meso and meta tarsi very long. Claws long and slender, smooth and stongly curved, without internal appendages.

Description from 1 Denham specimen at X10

Duffy, 1953. A monograph of the immature stages of British and imported timber beetles. London, Brit.Mus.(Nat.Hist) 1-350.
Palm, T. 1960 Biologiska studies over Stenocorus meridianus. Opusc.ent 25:138-145.
Rix 2000 In Wildlife 2000 a status report for Hillingdon. Hillingdon Natural history society page 101.