214 THE INSECT WORLD. 



and sometimes August, the caterpillar of which lives on the leaves 

 of willows, poplars, and fruit-trees ; and the Poplar Hawk-moth 

 (Smerinthus populi, Fig. 199), whose caterpillar (Fig. 200) lives 

 on the poplar, the aspen, and sometimes on the willow and birch. 



The division of Bombydna contains the largest of moths ; and at 

 the same time species of a middle and small size. These moths 

 take no nourishment, and live only for a short time, long enough 

 to propagate their species. They rarely fly during the day, 

 only showing themselves in the evening. The group is dispersed 

 over nearly all parts of the world, and may be recognised by 

 the antennaB generally being cut like the teeth of a comb in the 

 males, by their thick, strong bodies, and in the majority of cases 

 by their large head, by their wings more or less large, and by 

 their heavy flight. 



In the Bombycina are found the genera Sericaria, Attacus, 

 Bombyx, Orgyia, Liparis, &c. 



It is to the genus Bombyx that the silkworm belongs, that 

 celebrated insect called by Linnaeus Bombyx mori, a name which 

 reminds us at the same time of its most ancient denomination, and 

 of the mulberry tree, on which these caterpillars feed. 



M. Gruerin-Meneville has called the silkworm "the dog of 

 insects/ 1 for it has been domesticated from the most ancient times, 

 and has become deprived of great part of its strength in the 

 process. The moth of the silkworm can no longer keep its 

 position in the air, or on the leaves of the mulberry when 

 they are agitated by the wind. It can no longer protect itself, 

 under the leaves, from the burning heat of the sun and from 

 its enemies. The female, always motionless, seems to be ignorant 

 of the fact that she has wings. The male no longer flies ; he flutters 

 round his companion, without quitting the ground. It ought, how- 

 ever, to be possessed in the wild state of a sufliciently powerful 

 flight. M. Ch. Martins found that after three generations reared in 

 the open air, the males recovered their lost power. 



Before speaking of the different phases of the life of the silk- 

 worm and the rearing of this precious insect, we will say some- 

 thing about the origin and progress of the silk trade, one of the 

 most important branches of commerce in the South of Europe and 

 in the East. 



