The female emperor moth has grey wings, with an eye-like spot on each wing. The male is smaller and more brown in colour. The wing length is 21–35mm.
Emperor moths are well camouflaged amongst the heather. When the moth is at rest its wings open flat. When threatened, the emperor moth vibrates its wings using the eye spots to startle predators, giving the moth a chance to escape.
Unlike most other moths the emperor moth is active during the day.
The caterpillar of the emperor moth grows to 60mm long. The caterpillar is bright green with black bristles and bands of black circles. The caterpillar is well camouflaged, especially in heather which is its main food plant. The emperor moth is found throughout Scotland, although it is not found on the Shetland Isles or on the Isle of Lewis. The emperor moth lives in heather moorland and open woodland. The heather moorland of Scotland, where most of the moths live, is decreasing in area.
A man found a cocoon of an emperor moth and took it home so he could watch the moth come out of the cocoon. One day a small opening appeared. The man sat and watched the moth for several hours as it struggled to force its body through that little hole. Then it seemed to stop making any progress. To the man it appeared as if the moth had gotten as far as it could in breaking out of the cocoon and was stuck.
Out of kindness the man decided to help the moth. He took a pair of scissors and snipped off the remaining bit of the cocoon so that the moth could get out. Soon the moth emerged, but it had a swollen body and small, shrivelled wings. The man continued to watch the moth, expecting that in time the wings would enlarge and expand to be able to support the body, which would simultaneously contract to its proper size.
Neither happened. In fact, that little moth spent the rest of its life crawling around with a swollen body and shrivelled wings. It was never able to fly.
The man in his kindness and haste didn’t understand that the restricting cocoon and the struggle required for the moth to get through the tiny opening were God’s way of forcing fluid from the body into the wings so that the moth would be ready for flight once it achieved its freedom from the cocoon.
Just as the moth could only achieve freedom and flight as a result of struggling, we often need to struggle to become all God intends for us to be. Sometimes we wish that God would remove our struggles and take away all the obstacles; but just as the man crippled the emperor moth, so we would be crippled if God did that for us. God doesn’t take away our problems and difficulties, but he promises to be with us in the midst of them and to use them to restore us, making us into better, stronger people. (See 1 Peter 5:10.)