The antennae also have a whitish band near the tips and there is a small yellowish-white spot or dash at the rear of the thorax.

The caterpillars spend two years feeding near the base of a tree trunk or in the roots, overwintering as larvae.

Size and Family

  • Family – Clearwing moths (Sesiidae)
  • Small Sized
  • Wingspan Range – 24-28mm

Conservation status

  • UK BAP: Not listed
  • Nationally Scarce B

Caterpillar Food Plants

Alder (Alnus glutinosa) and birches.

One of only three species of this family that are found in the British Isles. The adults are incapable of feeding. They overwinter twice as part-grown larvae in reed stems below the water surface, then in the third year the caterpillars can be found from July to the following May moving between reed stems.

One of only three species of this family that are found in the British Isles. The adults fly during at night but can sometimes be seen resting during the day on tree trunks. The adults are incapable of feeding. The caterpillars can be found from August to the following May. They overwinter two or three times as larvae in the stems and branches of trees.

Their English name is derived from the males of the spp. humuli which are entirely white, however the females are larger with a striking yellow forewing with distinctive orange markings. The Shetland spp. thulensis is smaller with a creamy white forewing marked with brown. When at rest they hold their elongated wings almost vertically against their body.

The markings are clearly visible as the wing rests with both wings held flat. The extent of the border marking can vary, sometimes extending to the centre of the wings towards the body.

The adults fly at dusk and are attracted to light. The caterpillars can be found from mid-July to mid-September before overwintering as pupae underground.

The adults fly at night and are attracted to light, especially the males. They can sometimes be found resting on tree trunks or posts during the day. The caterpillars can be found from April to June after they have overwintered as eggs.

A white moth with small black spots on the forewing, however the number of black spots varies greatly from largely white examples which are almost entirely plain to those with many more spots that may even join together to form streaks along the wing veins.

The white wing colour can also vary with creamy-buff or even brown examples often found in Scotland.

The hairy larvae can be seen from July to September which then overwinter as pupae among plant debris.

The wings are held close to the body at rest, steeply angled. They are very similar in appearance to the Lesser Swallow Prominent but can be distinguished by the white wedge on the trailing edge of the forewing which is longer, narrower and more greyish-white in the Sallow Prominent.

The larvae can be seen from June to July and late August to September which then overwinter underground as pupae.

The usual form in rural areas is all white peppered with black dots on both the wings and body. Black forms known as f. carbonaria were once dominant in industrial areas with high levels of pollution although their frequency has been steadily declining in recent years. Intermediate forms known collectively as f. insularia are variable between the light and dark forms.

The larvae can be seen between early July and late September before they overwinter as pupae just below the ground.

Size and Family

Light green in colour with black markings, some of which are edged in white.

The adults feed at ivy flowers and overripe berries. They overwinter as eggs on branches or in bark crevices of the foodplant. The young caterpillars will first feed inside an opening bud and then when they are larger they will feed only at night, spending the day hiding in a bark crevice on the tree trunk.

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