134 OUR INSECT FRIENDS AND FOES 



restless little creatures, and flutter round the 

 females with rapidly vibrating wings; they re- 

 main close to the spot on which they emerged 

 from the cocoon, and do not long survive their 

 mates. 



The eggs, when first laid, are a bright yellow 

 colour, and soft and sticky to the touch ; they 

 rapidly harden, and gradually change in hue to 

 brown, then to reddish-grey, and finally to a 

 slate colour. They remain thus from the 

 autumn (when they are laid) until the spring of 

 the following year is fairly advanced, when they 

 assume a bluish tint, and then, through suc- 

 cessive changes, pass from blue to violet, slate, 

 yellow, and finally to an ashy white. 



The egg is now on the point of hatching, and 

 is semi-transparent ; if examined with a pocket 

 magnifying lens, a black spot and a brownish 

 crescent may be seen within the envelope. The 

 black spot is the head of the tiny caterpillar, and 

 the dark crescent the minute body, which is 

 already covered with fine hairs. 



When quite ready to emerge the larva gnaws 

 its way out of the egg, and directly it is released 

 from its prison attaches a fine silken thread to 

 the nearest object at hand. The little creature 

 is at first almost black, covered with hairs, and 

 about a quarter of an inch in length. It rapidly 

 increases in size until it has attained its full 

 growth, when it measures about three inches 

 long. 



During the period of growth the caterpillar 

 moults, or casts its skin, four times ; after the 

 first moult, which occurs when the silkworm is 



