54 THE BIOLOGY OF THE SEASONS 



bury themselves for pupation. When they find it, they 

 mass together, and move round and round paying out silk 

 and loosening the soft soil. In this way they gradually sink 

 below the ground, where they lie dormant, undergoing 

 metamorphosis through the summer. The moths emerge 

 in autumn. 



These destructive caterpillars are familiar sights in some 

 parts of the Riviera, and they have many interesting 

 features in addition to their processions. Thus the loosely 

 attached hairs, which are covered with fine recurved 

 booklets, are very irritant to many people (and not at all to 

 others), causing a rash on the skin when the caterpillars 

 are handled. 



Mr. W. F. Kirby writes : " The hairs of the proces- 

 sionary larvae, which are very loosely attached and studded 

 with exceedingly fine and recurved hooks, cause violent 

 inflammation on the skin of men and animals, partly by thus 

 adhering to it, and partly in consequence of a fine dust with 

 which they are covered. On this account the neighbour- 

 hood of the nests of these larvae, which are intermingled 

 with these hairs, is dangerous, for the surrounding air is filled 

 with loose hairs and dust, which are liable to be inhaled, and 

 to give rise to internal inflammation and swellings, which 

 have sometimes caused death. The inflammation caused 

 by the hairs of the larvae may be relieved or averted by 

 rubbing the skin with oil." 



Another feature in the life of caterpillars is their enormous 

 appetite. Some of them seem never to stop eating, and 

 a species of Polyphemus is said to eat 86,000 times its 

 own weight in a day. The contrast between this and the 

 dainty meals of the butterfly or its not infrequent fasting 

 is almost diagrammatic the larva is the nutritive, vegeta- 

 tive, growing phase ; the adult is ascetic and reproductive. 

 In the great majority of cases caterpillars are vegetarian, 



