Tillus elongatus (Linnaeus, 1758)       Notable B

Female
Local throughout England except the far north, this insect occurs upon and within dead or decaying Beech usually in company with Ptilinus pecticornis Linnaeus upon whose larvae it preys. Active from the first hot days in May the adults may be found on standing trunks which are dry, smooth and devoid of bark. By the beginning of June they may be very common.

Around a decaying Beech stump some 4m. high in Cassiobury park in June 2006 they were active from ground level to the top of the stump, at any one time during bright sunshine there were between 30 and 50 specimens, mostly female, patrolling up and down the trunk, some in copulation while others could be seen around the top of the stump flying through swarms of Ptilinus. Those patrolling the stump ignored both the ants and the Ptilinus which were around them in large numbers. Ocassionally Tillus will began searching a small area often disappearing into a ready made tunnel, not the emergence holes of Ptilinus which pepper the whole trunk and are much smaller than those of Tillus, both males and females were seen to do this. Sometimes they were seen emerging from the wood; having bored an exit hole the beetle partly emerged, remaining stationary for ten minutes or so with the head and thorax exposed. They are also active nocturnally when the temperature is high.

7-9mm. Entirely black but for the red thorax in the female. Head across eyes slightly wider than thorax, evenly punctate and pubescent. Eyes excised in front accomodating antennal tubercles. Pronotum elongate, cylindrical and broadest anteriorly, finely bordered on front and hind margins. In male more heavily punctate and transversely strigose. Elytra with strongly puntured striae, generally leaving one or two abdominal segments exposed in set specimens. More dilate posteriorly in Female. Tarsal joints 2-4 bilobed. Claws brown, each with two long teeth and a short and sharply pointed basal one. Entire insect pubescent.

Description from 6 Watford specimens at X20


Female

Male

Female

Male

Female

Male

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