The Hepalidae are considered "primitive" moths. There are 500 species world wide. They are widespread in central and northern Europe, but only 5 British species; all fairly common.
The adults fly from dusk to darkness, then take up the typical resting position seen below in the Ghost moth. In many species the males make display flights or dances to attract females, sometimes releasing scents detectable even by humans as they dance. The adults are all medium to large sized (females usually larger than males) with short antennae, and all - as the common name implies, are swift and strong fliers.
The British adults do not have a functioning proboscis, so they cannot feed. As can be seen in the Ghost moth below the antennae are short.
The caterpillars tend to feed on roots at ground level, and are usually light coloured. Many take 2 years to reach adulthood.
The Ghost moth's range extends eastward across Europe to western Asia. In Britain it is common.
The eggs are laid in June. Actually they are not really laid, but are scattered by the female as she flies over the foodplants. There is usually one generation a year.
The caterpillar (above) hatches after around 2 weeks, and feeds underground on plant roots until the following May, although some may not pupate until the following year. It is up to 40 mm long, pale dirty- white with a shiny red-brown head and grey-brown spots. It is found in fields, gardens, and anywhere its foodplants grow. It feeds on a variety of herbaceous plants including grasses, nettles, docks and wild strawberries.
Pupation takes place underground in a brown cocoon (see above). The pupa works its way to the soil surface before the adult emerges, and the husk of an empty one can sometimes be found sticking out of the ground with just the tail section in the soil.
The adult (above and below) hatches out at the end of May and in June. The adult male (left) is pure white, giving it its common name, and the female is larger and a yellowish - tan colour. The male dances over the grasses at dusk to attract the female to mate. It is believed that the male may have UV patterns invisible to humans, but visible to the females sitting in the grass.
Wing length is 21 - 35 mm with the female being larger than the male. It is the largest species of the family found in Britain. The adults fly until early August. The males gather in groups after dusk to attract females.
Map-winged swift, Korscheltellus fusconebulosa, above and below. It is also known as Hepialus fusconebulosa, and Pharmacis fusconebulosa. It is more common in the north and west of the U. K. and flies from June to August.It is found in moorland, heathland, open woodland, and in the Scottish islands on sand dunes. As with others in this family the adult does not feed.
It has a wingspan of 30 - 35 mm, and a forewing length of 14 - 26 mm. There is a pale version which is tan with a pale mark on each forewing. The sexes are similar.
The caterpillar lives underground eating bracken roots, grass roots and sometimes even potatoes. It pupates underground. The life cycle takes two years, so the caterpillar overwinters twice underground.