Magdalis barbicornis (Latreille, 1804)
This is a very local species throughout Europe extending north into Scandinavia and the UK, in central and southern regions it is generally common but further north scarce and sporadic, also recorded from Morocco, Algeria, Turkey and Georgia and adventive in the USA (California) since 1909. In the UK it is widespread and sometimes common though very local in the southeast and the midlands; the usual habitat is woodland margins, hedgerows and wasteland where the host plants, various Rosaceae e.g. Crataegus, Sorbus, Malus, Pyrus occur and in the past it has been a minor pest of fruit trees, especially Pyrus, in old and neglected orchards. Adults occur from late April to July when they may be beaten or swept from foliage, early in the season they feed on the underside of leaves producing a small area peppered with tiny, dark punctures, some of which penetrate the upper surface but this seems to do the host no harm. They mate in the spring and oviposition soon follows; eggs are laid in bark crevices and larvae bore down to the phloem to begin feeding, they soon penetrate the xylem and construct chambers in which they will develop through the summer and this may damage the tree as infected areas of wood may desiccate and die. In warmer regions they pupate in the wood during the summer to produce late summer and autumn adults which will overwinter in the wood, further north the larvae overwinter and pupate early the following year to produce spring adults. In South Hertfordshire and South Buckinghamshire it is locally common and we have recorded them from many widely scattered locations, the majority have been swept from Crataegus, often from plants in blossom.
3.1-4.1mm. Males are obvious from the modified antennal club, although those of M. cerasi are also modified but to a lesser degree, otherwise specimens will need to be examined critically. Dorsal surface and legs entirely dull black. Head with large convex eyes that are more prominent in the male, interocular distance a little less than the rostral width, surface weakly convex and finely punctured. Rostrum in lateral view forming an angle with the frons; as long as the head in the male, much longer than the head in the female. Antennae entirely pale or, commonly, with the club darker to pitchy; modified in the male with the club much longer than the scape, in the female about as long as the scape. Pronotum flat on disc but convex towards the lateral margins; quadrate and gently curved laterally in the female, transverse and much more strongly curved laterally in the male, surface densely and quite strongly punctured although there may be a smooth longitudinal area towards the front. Elytra elongate and almost continuously rounded apically, parallel-sided in the male, broadened towards the apex in the female; striae strongly and regularly punctured, a little narrower than the interstices which are weakly convex and rather densely cross-strigose. Legs entirely dark or, occasionally, with the tarsi lighter, all femora smooth ventrally.