|Agrilus sulcicollis Lacordaire, 1835|
|Introduced to the British list in 1994 by Trevor James (1994) from a single
female found on recently cut oak logs in Cowheath wood, s.e. Herts. There are now four records (1995-2000) local to
this first find on the NBN (August 2009) while Alexander
lists records from Essex (1997), Middx (1998) and Beds (2000) and so our donated specimens taken on dead
Quercus at nearby Bricket wood common (May 2009) is perhaps not surprising. What might be surprising is the
lack of futher records in the fifteen years since the first find. Bily
gives some information on the species biology; larvae develop over one or two years under bark of living
Quercus spp. with pupation occuring (usually) within the bark. Adults occur from May to July on leaves and
branches of the host and are known to settle on freshly cut timber (Schaefer, 1949).
A relatively large and robust species with the upper surface brilliant metallic green, dark (to virtually black) with green overtones, through bronze and blue to violet. Underside black or very dark with a metallic tinge.
6.0-8.5mm (Bily) Head deflexed and strongly flattened vertically in front of eyes, surface metallic with close and quite strong puncturation, pubescence very short. Puncturation longitudinally confluent above eyes, transversely seriate in front. Eyes strongly transverse (to body axis). Antennae metallic, strongly serrate from fourth segment. Pronotum parallel in front of middle, sinuate and narrowing to perpendicular hind angles. Front margin gently bisinuate, hind margin strongly bisinuate; matching the base of the elytra. Strongly convex anteriorly becoming flatter towards hind margin, surface with strong transverse microsculpture in sinuate lines. Raised ridge inside hind angles curved; about 2/5 pronotal length. Elytra long and thin, surface densely covered with weakly raised, wide and flat granules and very short, backwardly recumbent, dark pubescence (just visible at X20 in side view); about 3.5 X longer than the basal width, flattened above and dilated behind middle, suture raised in apical third. Basal margin strongly raised to meet pronotum. Humeral prominence well developed, lateral margin strongly sinuate (view from side). Apices rounded. Legs dark metallic, long and narrow. Tibiae without spurs. Tarsi 5-5-5; basal segment long and thin, second segment short, third weakly lobed below, fourth strongly bilobed, fifth long and slender. Claws sharply appendiculate.
Description from 1 Watford specimen at X20
Identifying Agrilus sulcicollis
Agrilus species are separated from our other buprestid genera by a combination of size, which varies from around 4mm (small angustulus (Ill)) to around 13mm (large pannonicus Pill. and Mitt)), rounded or more or less truncate elytral apices (ie not acuminate as in Melanophila), pronotum with bisinuate basal margin and microsculpture consisting of transverse sinuate ridges, and a large scutellum ie about a quarter of the pronotal width across the base (the base of the scutellum, it must be noted, is usually hidden beneath the posterior pronotal margin).
There are currently six species on our British list (Duff, 2008). These are readily separated into two groups of three according to the form of the apical margin of the fifth abdominal sternite; in viridis (L.), sinuatus (Ol.) and biguttatus (Fab.) this smoothly rounded so forming a single curve. In our three remaining species; angustulaus (Ill.), laticornis (Ill.) and sulcicollis Lac. this sternite is emarginate (obvious and X20) and it is these species that interest us here.
In laticornis the prosternal process is widely dilated towards the apex, beyond the level of the middle of the procoxae - in combination with the emarginate fifth sternite this will identify laticornis among the British fauna.
In both angustulatus AND sulcicollis this process is parallel sided or only slightly widened between the coxae, becoming constricted and then produced towards the apex. Morphological characters allowing the separation of these species are provided by Bily:
1. Vertex (measure shortest distance between eyes) narrow; about 1/3 the width of the anterior pronotal margin. Eyes weakly convex. Prehumeral pronotal carinae (just inside the hind angles) short and curved. Elytra more robust.....sulcicollis Lac.
-- Vertex wider; about 1/2 the width of the anterior pronotal margin. Eyes strongly convex. Prehumeral pronotal carinae long and straight; reaching almost to middle of pronotum. Elytra more slender......angustulatus (Ill.)
The aedeagus of both species are given as line drawings by Bily; the robust and highly asymetrical form of sulcicollis is distinct. That of angustulus is symetrical (from above). All species are also keyed by Thery (1942) who also gives drawings of both aedeagophores; this is accessible online (in french).
Schaefer, L. 1949 Les Buprestids de france. Miscellaenea Entomologica (supplement) Cabinet Entomologique E.Le Moult
Thery, A. 1942 Col.Buprestidae Faune de France 41. Office Central de Faunistique
We have to say a big thank you to Koen Smets who kindly donated to the WCG both the specimens pictured. Koen's original identification was kindly verified by Trevor James (the Herts county recorder and, as above, the original discoverer of the species in Britain).