The Sphingidae comprises about 1,500 species and occurs worldwide, with most found in the tropics. There are nine species resident in the British Isles. Eight others occur as immigrants, some regularly breeding, but the early stages are unable to survive the winters, although one species, the Hummingbird Hawkmoth, hibernates as an adult in south-west England. Hawkmoths are impressive medium to large moths, often strikingly coloured, and include the biggest moths in Britain in terms of wing-span and body size. They are known as hawkmoths because of their fast and manoeuvrable flight and the large size of many species.
The Sphinginae include the largest hawkmoths. They tend to hold their wings close to the body at rest. some have very long tongues and however in front of the flower to feed, like the Macroglossinae, while others, such as the Death’s Head Hawkmoth, have reduced tongues but may still feed.
Within the Smerinthinae, the proboscis is reduced in length and the moths typically do not feed. The hindwings often have circular patches or eye-spots, and the leading edge of the hindwing sometimes projects beyond the leading edge of the forewing at rest. The females are generally bigger than the males, and males rest with the tip of the abdomen curled upwards.
The Macroglossinae have long tongues, hence the name, and the group includes may species which hover to take nectar from flowers by day or at dusk. Two species have evolved a resemblance to bees, with largely transparent wings and squat bodies. Many of the Macroglossinae look like jet-fighters. Their caterpillars often have eyespots on the body segments.
The eggs are attached to the foodplant, usually singly or in pairs. The larvae are not hairy and most species have a horn at the tail end. This tends to be long and well developed in Sphinginae and Smerinthinae, while in the Macroglossinae the tail horn is often reduced; in the Small Elephant Hawkmoth it has disappeared altogether. The larvae feed on the leaves of both woody and herbaceous plants. The pupae of many species can be found by searching at the base of the larval foodplant, either among moss and leaf litter, or by digging in the soil.
With the exception of day-fliers, the adults of most hawkmoths come regularly to light, and are occasionally found at rest by day, usually when newly emerged. Those which feed can be found by searching out their nectar plants, to which they will return repeatedly. A number have brightly-coloured hindwings and flash these when disturbed, in order to deter predators.
(Taken from Waring and Townsend’s Field Guide to the Moths of Great Britain and Ireland)