81 



interval in existence ; let us I say, consider 

 these facts and compare them with the 

 small stock of comparative knowledge we 

 possessofthispaitofnatural economy. The 

 farmers in Scotland now practise Reau- 

 mur's method of rubbing the eggs of poul- 

 try over with any oily substance to pre- 

 vent their becoming putrid, &c. by which 

 their vitality is preserved for a length of 

 time. The eggs of many insects are co- 

 vered with a mucus which has no doubt 

 the property of preserving them, as these 

 eggs- are hatched by the warmth of the at- 

 mosphere, and their hatching may be re- 

 tarded, as is instanced in the silk-worm, 

 and there are some species that areknown 

 to live for many years both in the chry- 

 salis and egg state, until a favourable 

 season arrives for their coming forth. 

 I this season released a pupa * from a 



* It should be observed that some caterpillars 

 when turning into the pupa state, exude from their 

 mouths a hard substance like glue, which forms their 

 cell, and this being attached to such places as 

 they find convenient to lie up in, they remain 

 perfectly secure from danger. 

 E 5 



