The Zoologist— June, 1868. 1231 



front legs, while the two hind pair are detached ; in this position it 

 remains for some time, evacuating the contents of the alimentary canal, 

 until finally a gelatinous, transparent, very caustic fluid, looking like 

 albumen, or the white of an egg, is ejected: this is a preparation for 

 the long catalepsy that the worm is about to fall into. It now feels 

 with its head in all directions to discover any leaves to which to 

 attach the fibres that are to give form to the cocoon. If it finds the 

 place suitable it begins to wind a layer of silk around a twig; then a 

 fibre is attached to a leaf near by, and by many times doubling this 

 fibre, and making it shorter every time, the leaf is made to approach 

 the twig at the distance necessary to build the cocoon : two or three 

 leaves are disposed like this one, and then fibres are spread between 

 them iu all directions, and soon the ovoid form of the cocoon dis- 

 tinctly appears. This seems to be the most difficult feat for the worm 

 to accomplish, as after this the work is simply mechanical, the cocoon 

 being made of regular layers of silk united by a gummy substance. 

 The silk is distributed in zigzag lines of about one-eighth of an inch 

 long. When the cocoou is made the worm will have moved his head 

 to and fro, in order to distribute the silk, about two hundred and fifty- 

 four thousand times. 



After about half a clay's work the cocoon is so far completed that 

 the worm can hardly be distinguished through the fine texture of the 

 wall : then a gummy resinous substance, sometimes of a light brown 

 colour, is spread over all the inside of the cocoon. The larva con- 

 tinues to work for four or five days, hardly taking a few minutes of 

 rest, and finally another coating is spun in the interior, when the 

 cocoon is all finished and completely air-tight. The fibre diminishes 

 in thickness as the completion of the cocoon advances, so that the last 

 internal coating is not half so thick and so strong as the outside ones. 

 During the process of spinning, the worm contracts and diminishes in 

 size as the silk reservoirs empty. Six or eight days after the beginning 

 of the cocoon the worm casts its last larva-skin, and theu appears 

 under a very different form — a transitory one, which is neither worm 

 nor moth : it is the chrysalis or pupa. When the chrysalis comes out 

 of the larva-skin, if observed closely, it will be seen that its resem- 

 blance to the perfect insect is striking ; the antenna?, the head, the 

 legs and abdomen resemble very much those of the moth. The wings 

 only are very small, but in a few minutes they grow to about half the 

 size of the abdomen. The legs of the chrysalis, at least the tarsi, are 

 enclosed in the articulated leg of the larva, the wings are folded under 



