Black-veined White Aporia crataegi
Conservationists have recently announced that the climate in Britain is becoming more suited to the needs of this now extinct species and that it may yet become a re-established British species.
Larvae do well sleeved on Hawthorn (their preferred foodplant), Plum, Blackthorn, Apple. The larvae live in a cluster. These will produce butterflies this spring.
Summer larvae spin a very small and concealed web on the branch, in which they hibernate. Leave the sleeve untouched for the winter. In spring they awake as soon as the buds burst, and begin to grow very quickly. They pupate often collectively, making very brightly coloured, angular pupae which are greenish white, with contrasting markings in black and yellow.