OF INSECTS. 227 



Louse Notes and Queries on Insect-metamorphosis. 



The maggot or caterpillar changing in every part, losing the old, and 

 forming new out of the same materials, may illustrate the changes that 

 take place in the matter of other animals. It may explain the change 

 from cartilage to bone ; but, probably better, the changes that take place 

 in newly-formed parts. 



The grub, maggot or caterpillar [of an insect] may be reckoned more 

 simple than when [it becomes] a fly ; at least they are more simple in 

 their parts of digestion, having hardly any intestine ; which would 

 incline one to suppose that an increase of parts, which of course produces 

 an increase of action, requires an increase of intestine or digestive 

 powers. 



In insects, do the brain and nerves change equally with the other 

 parts of the body? or does the same construction of brain, and identically 

 the same nerves, answer two purposes 1 ? 



When an insect forms itself into the perfect state in its pod, it cannot 

 live long in that situation, for then it is a perfect animal, and immedi- 

 ately requires food. Therefore such insects as enclose themselves in the 

 autumn, to live in that pod through the winter, lie dormant in the 

 maggot or caterpillar-state till the spring or summer before they change 

 into the fly. 



Relation of generative Parts to Grade of Species. 



The parts of generation in the more imperfect animals increase in size 

 almost in proportion to their imperfect grade, so that the most imperfect 

 are almost wholly genitals, as the polypus and tapeworm. 



Loose Notes and Queries on Generation. 



Is not the circumstance of mules not breeding a strong presumption 

 that generation is performed by a mixture of perfect seed belonging to 

 both sexes, and not dependent on one only ? It shows that the seed of 

 two different perfect animals cannot produce a perfect animal ; owing, 

 we may suppose, to that produce not being capable of producing perfect 

 seed. 



1 Had Hunter been acquainted with the great work of Lyonnet, 'Traite ana- 

 tomique de la Chenille que ronge le Bois de Saule,' 4to. 1762, he would have found 

 therein the answer to his question. See the abridged residts of Lyonnet' s and later 

 investigations of this interesting subject in my 'Lectures on Invertebrata,' ed. cit., 

 p. 359-366. 



q2 



