42 THE BUTTERFLY VIVARIUM. 



sulphur coloured, then green, then rose colour, and 

 becoming eventually black. The size of the eggs of 

 insects is, as I have noticed above, very various, and 

 not always corresponding to the size of the parent. 

 Those of some small parasitic insects, for instance, 

 are nearly as large as the parent itself, while 

 those of other classes of Butterflies are infinitely 

 smaller. The largest insect egg known is that of 

 a species of Phasma, one of the singular tribe of crea- 

 tures popularly termed Stick-insects, having really 

 the appearance of a portion of a branch furnished 

 with long artificial legs. The egg in question is 

 described in the " Linnsean Transactions"* as being 

 as large as that of a Humming-bird, Avhile those of 

 many species of Ephemera are smaller than the 

 finest grain of sand. 



It has been remarked that the eggs destined to 

 become females are generally larger than those 

 containing the germs of males — a peculiarity which 

 is especially visible in those of Ants, as noticed by 

 Goulet ; while Reaumur asserts that it is the con- 

 trary with respect to the eggs of Bees. 



In some cases the eggs of insects increase in size 

 after they are laid ; those of certain Ichneumons, for 

 instance, positively " grow," as do likewise those of 



* Vol. iv p. 18. 



