The Moths and Butterflies 429 



the back; A. senatoria (Figs. 614 and 615) is like A. virginiensis, but lacks 

 the transparent place in the middle of the wing; the caterpillar is black with 

 four stripes. All these Anisota larvae feed on oaks, and that of A . senatoria 

 also on blackberries and raspberries. Sphingicampa (Adelocephala) bicolor 

 is a beautiful moth with brown fore wings and dark-pink hind wings with 

 dusky dots, which is not uncommon in the Mississippi Valley and southern 

 states; its larvae feed on the locusts and the Kentucky coffee-bean. In the 

 southwest are two or three species of the genus Syssphinx resembling Sphingi- 

 campa bicolor, but one, S, heiligbrodli, in Arizona, has iron-gray fore wings. 

 Now unknown in wild condition, the long-cultivated Chinese or mulberry 

 silkworm, Bombyx mori, is spread over most of the world, living exclusively, 

 however, under the personal care of man. Indeed it is often said that the 

 worm is so degenerate, so susceptible to unfavorable circumstances, that 

 it could not live out of doors uncared for. As a matter of fact, however, I 

 have bred moths from silkworms placed 

 exposed on mulberry-trees in California 

 immediately after the first moult. And 

 these individuals experienced consider- 

 able hardship in the way of low temper- 

 atures and dashing rains. The heavy 

 creamy-white moths, with wing expanse 

 of if inches, take no food at all, and 

 most of them cannot even fly despite FlG 6l7 ._ M ulberry silkwom, show- 

 their possession of well-developed wings, ing front view of head and thorax, 

 so degenerate are the flight-muscles from ( From life; natural size ' ) 

 generations of disuse. The eggs, about 300, are laid by the female on any 

 bit of cloth or paper provided her by the silkworm-growers. They are yellow 

 at first, but soon change to a slaty color due to the beginning development 

 of the embryo. In the annual race of silkworms, i.e., the variety which 

 produces but one generation a year as compared with those others which 

 produce two (bivoltins), three (trivoltins), and even five or six (multivoltins), 

 the development of the eggs soon ceases, and they go over the winter, hatching 

 in the following spring at the time the mulberry-trees begin leafing out. 

 The larvae (Figs. 616 and 617) must be well fed with fresh mulberry or osage- 

 orange leaves (they may at a pinch be carried through on lettuce) from which 

 all rain- or dew-drops should be wiped off. The worms moult every nine 

 or ten days, ceasing to feed for a day before each moulting, during the forty- 

 five days of larval life, spinning before the last moult (pupation) the dense 

 white or golden silken cocoon which is, to man, the silkworm's raison d'etre. 

 In this spinning the thread is at first attached irregularly to near-by objects, 

 but after a sort of loose net or web has been made the spinning becomes 

 more regular, and by the end of three days a thick firm symmetrical closed 



