Large Tortoiseshell; Olmera

Medium size butterfly that looks very like the Small Tortoiseshell (Aglais urticae). 4.5 to 5.5 cm wingspan, females 0.5 cm more. The upper side of the wings is orange with dark blobs. The underside of the wings is dark brown with a paler band. The wing edges are irregular.

The adult insect (imago) over-winters in dry dark places, such as hollow trees or out buildings. In late February or early March the butterflies emerge and mate. The females lay their pale green eggs (ova) in a continuous band around the upper twigs of Elm (Ulmus spp.), Sallow (Salix caprea and Salix viminalis), Pear (Pyrus spp.), and Prunus spp. trees. The caterpillars (larvae) are gregarious, and systematically strip the topmost twigs of the tree bare. They seem to have little defence against predation by birds.

The full grown larva spins a silk girdle around a twig further down the tree, and hangs from this by means of hooks (cremasta) at its rear end, to pupate. The chrysalis (pupa) is greyish-brown with a slight silvery sheen. There is only one generation per year, and the imagos emerging in mid summer seek out sources high in sugar to fee