Clitostethus arcuatus (Rossi, 1794) Endangered
This extremely local coccinelid has been recorded on several occasions from southeastern England and the midlands; Surrey, Berkshire, Oxfordshire, eastern Suffolk and Leicestershire and Rutland before 1970 and from Oxfordshire and eastern Suffolk post 1970 (Hyman and Parsons). Three further records are given by Welch and Jukes (1999) from Northamptonshire (1995), Norfolk and Hampshire, in each case from malaise traps. Typical habitat is deciduous and coniferous woodland (Majerus and Kearns, 1989) where they are associated with Ivy growing on trees, although Hyman and Parsons give 'most records are from beating Ivy, particularly that growing on buildings and walls and possibly also on quarry and rock faces'. The adults are predatory, feeding on whitefly, and winter is probably passed in this stage (Hyman and Parsons), they have been recorded from February, June, July, August and October. The species may be threatened by the removal of old ivy but we have no such problem locally where dense and luxuriant growths occur throughout our area; such plants, often exceeding 75mm in girth at ground level, growing on trees throughout local woodland have been sampled regularly over the past few years in search of the beetle but without success, light trapping in suitable habitats has also proved fruitless. Our single local record is from a Watford town centre garden on 29/06/08; a single specimen was found while pulling apart a sample of dry and decayed grass clippings from the edge of a compost heap over a white sheet, under these conditions the adults are cryptic and remain still for some time after being disturbed. Upon identifying the specimen several other samples were examined but without success, prior to this the compost had been sampled regularly throughout the year, both deep and surface samples having been extracted. A quick inspection of adjacent gardens failed to reveal any ivy but interestingly, there is a mature Viburnum tinus, complete with aphids, only three metres from the compost; Shirt (1987) records a breeding colony of Clitostethus on Viburnum tinus infested with whitefly found by N.J.Mills.

1.5mm. At X40 the horseshoe shaped yellow mark extending across the elytra is very distinctive and when combined with a second, variously developed, arcuate yellow mark posterior to this the pattern will serve to identify the species. The ground colour is usually dark but varies between black and dark brown. Entire upper surface with dense, backwardsly directed silvery pubescence. Appendages yellow although the antennae may be a little darker towards apex and the palps lighter, almost white. Head finely and sparsely punctured, black, yellow anteriorly. Pronotum transverse, very finely and sparsely punctured, finely bordered laterally and basally. Yellow with extensively dark discal area, in our specimen this dark mark does not reach front margin. Central dark mark may be reduced to marks along the basal margin and a few central spots (Welch and Jukes ibid). Elytra characteristically marked, margin also narrowly yellow around apex. Finely bordered and sinuate laterally, puncturation stronger than on pronotum and head.

Description from 1 Watford at X40

Shirt, D.B. 1987. British Red Data book 2 Insects NCC.
Welch, R.C. and Jukes, M.R. 1999. Clitostethus arcuatus from malaise traps in Northamptonshire, Norfolk and Hampshire Ent.Record 111:133-134