452 HABITATIONS OF INSECTS. 



grubs of different kinds which they rationally conceived 

 to spring from eggs, were chiefly at a loss to account for 

 the conveyance of these eggs into the middle of a substance 

 in which they could find no external orifice. They there- 

 fore inferred that they were the eggs of insects deposited 

 in the earth, which had been drawn up by the roots of 

 trees along with the sap, and after passing through differ- 

 ent vessels had stopped, some in the leaves, others in the 

 twigs, and had there hatched and produced galls ! Redi's 

 solution of the difficulty was even more extraordinaty. 

 This philosopher, who had so triumphantly combated the 

 absurdities of spontaneous generation, fell himself into 

 greater. Not having been able to witness the deposition 

 of eggs by the parent flies in the plants that produce galls, 

 he took it for granted that the grubs which he found with- 

 in them could not spring from eggs : and he was equally 

 unwilling to admit their origin from spontaneous genera- 

 tion, — an admission which would have been fatal to his 

 own most brilliant discoveries. He therefore cut the knot, 

 by supposing that to the same vegetative soul by which 

 fruits and plants are produced, is committed the charge of 

 creating the larvae found in galls a ! An instance truly hu- 

 miliating, how little we can infer from a man's just ideas 

 on one point, that he will not be guilty of the most pitiable 

 absurdity on another ! 



Though by far the greater part of the vegetable ex- 

 crescencies termed galls, are caused by insects of the genus 

 Cynips, they do not always originate from this tribe. 

 Some are produced by beetles, as those on the roots of 

 kedloek {Sinapis arvensis), which I have ascertained to 

 a Be Insectis, 233 &c. 



