Phymatodes testaceus (Linnaeus, 1758)
A local species across southern England and Wales to Nottingham and with single records from south Yorkshire and north Wales ( Twinn and Harding). The adults are active nocturnally and come readily to light, once attracted they are very energetic: either alighting and running fast or flying constantly until they escape. Furthermore they may be taken at a glance for a cantharid so one needs to remain alert to spot them. We have several records from MV during May and June in Watford town centre gardens. The preferred host is Quercus but the species is polyphagus, having been recorded from Fagus, Salix, Prunus avium, Castanea, Carya, Picea, Tsuga and Fraxinus (Hickin). Eggs are laid under the bark of standing dead timber or recently cut trunks. Larvae tunnel beneath the bark which may become loose with large populations, the galleries are densely packed with frass and may be extensive. This stage lasts for at least two years. A pupal cell is constructed under thick bark but if this is not available the larva will holllow out the xylem. The pupal stage lasts for about three weeks and adults emerge from May to July. The species is commonly imported with timber from Europe and although eggs are not laid in finished timber there have been many records of adults emerging from Oak block flooring. They have formerly been pests of considerable economic importance as the sapwood of Oak bloes may be almost totally destroyed (Hickin).

8-13mm. Typically entirely testaceous but very variable in colour through reddish to a deep blue-black (Hickin), a common form has the thorax reddish and the elytra blue (Joy, 1932). Head narrower than thorax, deflexed in front of antennal tubercles, finely punctate and pubescent throughout and with a distinct longitudinal impression between eyes. Antennae testaceous, extending back beyond elytral apices and with segment 3 about equal in length to 4. Distance between insertions wider than narrowest distance between eyes. Terminal segment of palpi dilated; hatchet shaped. Pronotum transverse, broadest behind middle, finely punctate and with long white pubescence. Without lateral borders or teeth and with a shining longitudinal raised ridge in centre of base. At least the lateral pronotal margins are yellow. Elytra finely and sparsely punctate and with recumbent pubescence, apices rounded and divergent, without spines. Never metallic. Abdomen may protrude beyond elytra but the wings, when folded normally, do not. Legs testaceous and long; tibiae at least as long as femora which are characteristically dilated. First segment of hind tarsus as long as remainder together.

It has been pointed out by Barclay (2003) that another cerambycid, Poecilium lividum (Rossi), may be confused with the present species. He considers Poecilium as unlikely to have occurred in the wild in historic times but points out that there are many specimens in older British collections. In P.lividum segment 1 of the hind tarsus is shorter than the next 3 together (Joy) and the third antennal segment is 'considerably longer than the fourth' (Barclay, 2003), in P.testaceous the third and fourth segments are equal. Barclay's notes provide an interesting insight into the occurence of P.lividum in Britain.

Description from 2 Watford specimens at X10

Barclay, M.V.L. 2003. On some British examples of Poecilium lividum from the New Forest: are they authentic? Coleopterist 12(3):114-118