GENERAL INTRODUCTION 33 



sounds. Those of the genus Macroglossum make a dull 

 knocking noise when moving the abdomen from side to side ; 

 those of Meganoton nyctiphanes a slight hissing noise. The 

 pupae are so seldom found in natural conditions that it is not 

 known what enemies they may have, but bred specimens 

 are frequently destroyed by the larvae of a small scavenging 

 fly which lays its eggs at the junction of the abdominal 

 segments. 



The moths are so swift on the wing, and so well concealed 

 by their colouring when resting, that they probably have 

 few enemies. They are, however, often captured and eaten 

 by bats. The species Acherontia lachesis and Langia zen- 

 zeroides, if disturbed when resting, alternately raise and lower 

 the body, at the same time partly opening and raising the 

 wings and producing a squeaking note. Many other species 

 vibrate the partially opened wings very rapidly, producing 

 a low humming note. Some of the day -flying species which 

 mimic bees bend the abdomen about as their models do when 

 stinging. 



The food-plants of Indian Hawk-Moths cover a very large 

 range, comprising some sixty widely separated families of 

 plants and hundreds of species, and including the largest 

 trees and small herbs, and even grasses. The larvae of some 

 species feed on a large number of plants of different families, 

 others confine themselves to a single family or even a single 

 species of plant, or whole genera choose their food-plants 

 from a single family. In some species the larvae become 

 so abundant in some localities in certain seasons as to cause 

 serious damage to the vegetation on which they feed. Those 

 ofHerse convolvuli and Acherontia styx sometimes devastate the 

 crops which form their food-plants ; those of Leucophlebia 

 emittens occur in immense numbers in some years, and destroy 

 the grass crop ; all Rubiaceous shrubs in certain areas are 

 sometimes defoliated by the larvae of Cephonodes hylas and 

 C. picus. The large larvae of Langia zenzeroides strip apple 

 and other fruit trees of their leaves. 



IV.— DISTRIBUTION, 



The Hawk-Moths are a widely distributed family, being 

 found in all parts of the world except the Arctic and Antarctic, 

 and occurring as stragglers even in the Arctic Regions. 

 Owing to their swift and powerful flight and habit of 

 wandering some of the species have a very wide range. This 

 habit also causes stragglers to appear in areas beyond their 

 normal range, but their permanent establishment in such 

 areas is often checked by a tendency of the females to become 



vol. v. D 



