The caterpillar lives under the bark of poplar trunks, and the moth flies in June and July.
Welsh Clearwing (Sesia scoliæformis).
As a British species this insect was first noted from Llangollen, in North Wales, somewhere about fifty years ago. In 1867 it was found to inhabit birch woods in the Rannoch district of Scotland, and later on its presence was detected in Sutherlandshire. It has been recorded from Hereford; one example was reported from Wiltshire in 1857; and two from Delamere Forest, Cheshire (1901 and 1905). Kane (Catalogue of the Lepidoptera of Ireland) states that moths have been taken at Killarney, and caterpillars obtained in the same district, and also at Kenmare.
The caterpillar (Plate [156], Fig. 3; after Hofmann) feeds on the inner layer of bark of large birch trees, and is full grown about May. It turns to a dark brownish chrysalis, in a cocoon formed close up to the bark, which thinly covers the outer end of the burrow. The moth flies in June or sometimes July. It
is of comparatively large size, and may be distinguished from the next species by the yellow belts on its body, and the chestnut coloured tuft at the tail. (Plate [154], Fig. 2.)
White-barred Clearwing (Sesia spheciformis).
Although generally smaller, some specimens run very close to the last species in size. It may be distinguished by the single belt on the body and the black tail (Plate [154], Fig. 3). One of the best known localities for the species in England is Tilgate Forest, in Sussex; but it also occurs in Hampshire (Basingstoke), Hereford (Tarrington), Worcestershire (Wyre Forest), Staffordshire (Burnt Wood), Cheshire (one, Delamere Forest, 1901), Denbighshire (Llangollen), Lancashire (Chat Moss), and Yorkshire (Bishop's Wood, 1894).
The caterpillar feeds in stems of alder, and is full grown in May of the third year after hatching from the egg. It is said that the chrysalis may sometimes be found by bending and twisting the stems of alder, so as to cause the thin skin of bark over the exit hole of the burrow to crack, and so disclose its whereabouts. The burrow is generally low down the stem. The moth is out in June and early July, and is sometimes to be seen on sunny mornings at rest on alder leaves, or flying over and around the bushes.
Orange-tailed Clearwing (Sesia andrenæformis).
Although known to be a British species since 1829, when a specimen was taken in a wood near Greenhithe, Kent, this insect continued to be very rare until quite recently. For a long time the caterpillar was supposed to feed in the stems of dogwood, but it is now known to live in the stems of the wayfaring tree (Viburnum lantana), and several specimens of the moth