GOSSAMER AND SILK 145 



more or less. Even the most persistent entomologists are 

 continually astonished by unexpected discoveries. 



There are many such discoveries yet to be made among 

 the silky cocoons concealed in every sort of nook and crevice 

 in the bark of trees, in the roots, on wood palings, under 

 stones. The commonest of all is the cabbage white which 

 hangs itself up very neatly, almost in a hammock. But the 

 silk is used in a hundred ways, to swing the spider or catch 

 its flies, or to spin a moth's cocoon or to line a hole. 



What most astonishes the Pasteurs coming with delight- 

 ful freshness to these subjects is the very short time during 

 which in many creatures the chrysalis stages last. There 

 are some cocoons designed to hold the pupa through winter 

 months ; but often, as in the silkworm, the chrysalis stage 

 is surprisingly short considering the astonishing transforma- 

 tion which proceeds. An egg, usually laid so that it adheres 

 to the leaf which is the caterpillar or worm's natural food, 

 may lie through a winter, though often, as again in the 

 cabbage white, they may hatch between spring and early 

 summer. The caterpillar may live in the grub state for 

 years as does the goat hawk moth grub which burrows into 

 our oaks. The perfect butterfly or moth, though usually it 

 is ephemeral, may safely hibernate through the winter, as 

 always do some of the Vanessae ; but the chrysalis case in 

 which the supreme transformation takes place is as a 

 rule only designed in spite of its perfection to last a few 

 weeks. A silkworm cocoon might be a life work. The 

 design is perfect. The outside of the case, in which the 

 twin threads are woven tighter, more compactly than the 

 rest, is designed to case-harden ; it forms a crust, a sort of egg- 

 shell, as some one said, for the soft interior, which is as 

 warm and snug a couch for the nursing of the coming Imago 

 as ever the spiders swung for Titania. Case and couch 



