Cryptophagus intermedius Bruce (Cryptophagidae): amended diagnostic characters and notes on an Essex population

摘要

In January 2008 about 12 metres of fresh ash branch lengths were added to my log pile and were subsequently heavily attacked by the scolytid Hylesinus varius (Fabricius). The following late autumn, long after the emergence of the adults, one length was briefly examined by the removal of a small piece of bark, finding hymenopterous larvae in many of the pupal cells. Further examination was left until the following spring when on 10 May one length was stripped of bark, which was still quite firmly attached although showing extensive lateral cracking along the lines of the varius egg galleries. Debarking dislodged many of the free hymenopterous pupae (chalcoids); also present were large numbers of fixed cocoons (braconids). Two Cryptophagus adults were under the bark and, in the dislodged material, two more adults and one pupa among the hymenopterous pupae. It seemed possible that the species could be the rare dentatus-group species intermedius, which has a known association with Hylesinus varius (Johnson, 1992). The detritus was retained and several more Cryptophagus emerged in due course. All proved to be dentatus-group.