332 TEXT-BOOK OF ZOOLOGY 



Family 5 : Bombycidae. 

 The Silkworm Moth (Bombyx mori). 

 (Breadth of moth 1^ inches.) 

 A. Distribution and Habitat. 



With the exception of the honey-bee, the silkworm moth is the only 

 insect which has been domesticated by man. In its native home, India 

 and China, where it is still met with in the wild state, the fine web of its 

 caterpillar has for thousands of years been manufactured into the most 

 costly of materials, silk. From China the culture of the insect spread 

 slowly to the West, but it was not until the year 536 of our era that the 

 eggs of the silkworm were for the first time introduced by monks into 

 Constantinople. On the shores of the Mediterranean the culture of the 

 silkworm gradually became a nourishing industry, inasmuch as the mild 

 climate of those countries is not only specially congenial to the insect, 

 but also to its food plant, the mulberry-tree. In England, owing to its 

 rougher climate, silkworms are kept for amusement but not for profit. 



In consequence of culture extending over thousands of years, the silk- 

 worm moth has become a very helpless creature. (Similar phenomena 

 may be noticed in many other domestic animals ; give examples.) It is 

 no longer able to fly, but can only flutter in a downward direction. The 

 young caterpillars no longer seek their food independently, and, like 

 the older ones, often bite through near the stalk the leaves on which 

 they sit, so that they fall to the ground. 



As is the case with all other domestic animals, several races or 

 varieties of silkworm have been produced by culture. 



B. Metamorphosis. 



Like all nocturnal Lepidoptera (see goat moth), the silkworm moth is 

 a very inconspicuous insect of yellowish-white colour. On the fore- wings 

 we usually find, in addition, several darker, indistinct transverse stripes. 

 In the natural state the male goes in search of the female, from which — 

 as is the case in all the Bombycidse — it is distinguished by the large 

 pectinate antennae, which are the seat of a very fine sense of smell 

 (compare with cockchafer). A few days after leaving the pupal envelope 

 the female lays its eggs, which may number up to 600, after which both 

 it and the male die without having taken any food (the proboscis is rudi- 

 mentary). During the winter the eggs are preserved in a cool airy spot. 

 (Why?) In the spring, with the breaking forth of the buds of the 

 mulberry- tree, the caterpillars, popularly but erroneously known as "silk- 



