46 INSECT TRANSFORMATIONS, 



frequent the same situations and might devour them. 

 The footstalks are so smooth and slender that these 

 grubs could not climb them, as we have proved by 

 experiment*. 



The ichneumon-fly {Ophion luteum), whose larvae 

 feed upon the caterpillar of the puss-moth, also 

 deposits eggs with a footstalk ; and what is most 

 singular, these larvae, after they are hatched, during 

 the first stage of their existence, continue attached to 

 the shells of their eggs. It is not till the puss has 

 formed her cocoon that they devour her, and spin 

 their own cocoons under its coverf. 



The eggs of insects do not seem to hold any 

 regular proportion, so far as regards size, with their 

 parent insects ; for some large moths lay very small 

 eggs, while others of a small size lay eggs consider- 

 ably larger. Kirby and Spence think it probable 

 that eggs which produce females are generally larger 

 than male eggs; with the exception of the hive-bee, 

 in which the reverse takes place. Huber, as we 

 have seen above, found the eggs of ants of different 

 sizes, from which he was led to discover that they 

 increase in size after being deposited. 



It has been remarked, that animals of prey are less 

 prolific than those which live on vegetable food ; 

 and a similar principle ajjpears to hold to a certain 

 extent amongst insects, the most prolific families 

 belonging, with ie\w exceptions, to those which devour 

 vegetable or animal substances beginning to decay 

 and putrefy. 



Thus it is that the eagle lays only two eggs, 

 while the wren lays eight, and the pheasant twenty- 

 four; and in the same way the dragon-flies (Lihellu' 

 Una, Mac Leay) do not lay above two dozen eggs, 

 the lace-winged flies (Hcmerobidts) still fewer, and 

 the noontide fly {Mcsembrina meridiana, MiiiGEN) 

 * J. K. t See Insect AiciiUecturc, pp. 195—325, 6. 



