53 PHYSIOLOGY OF THE EGGS. 



there is a species brought from Persia, which are 

 hatched three times a-year, and which will break 

 from the egg- in fifteen days, under a proper temper- 

 ature. But it is stated, as a circumstance out of the 

 ordinary laws of Nature, that in the year 1765, the 

 common sort hatched in the first year. 



In some species, the caterpillar is some hours in 

 extricating itself from the shell at hatching. In the 

 instance of the Sat.yrus mcera, Saturnia pavonia, 

 and various others, the shells are furnished with a 

 little lid, which, when the larva is completely deve- 

 loped, it can force up, and emerge at pleasure.* 



* BRAHM, 249. ROSEL. iv. 130. 



