58 STATES OF INSECTS. 



simultaneous changes of the whole integument, till the 

 animal appears in its perfect form with powers of repro- 

 duction ; in this kind the integuments are caducous. — In 

 man and most of the vertebrate animals there is a gradual 

 action of the vital forces in different organs till they are 

 fitted for reproduction ; accompanied, as progess is made 

 to the adult state, by the acquisition of certain organs, 

 &c. as of teeth, horns, pubes, feathers, &c. a Let us now 

 consider a little in detail the analogies that appear to exist 

 between the second and the first and third kinds. I shall 

 first consider the latter as the least obvious. That able, 

 judicious, and learned physiologist, Dr. Virey, has pointed 

 out no inconsiderable resemblance between the metamor- 

 phosis of the insect, and the changes, which he denomi- 

 nates a metamorphosis by metastasis, to which most ver- 

 tebrate animals are subject. In them, he observes, a state 

 analogous to the larva state begins at the exclusion of 

 the foetus from the womb ; it is deprived of teeth, and its 

 viscera are only accommodated to milk : in the cornute 

 species the horns are in embryo : the digestive system 

 now preponderates, and the great enjoyment is eating. 

 A second state, in a degree analogous to that of pupa, 

 commences at the period of dentition — the teeth now 

 produce another modification in the intestinal canal, 

 which becomes capable of receiving and digesting solid 

 food : during this period the vital forces are all tending 

 to produce the perfect state of the animal ; and in this 

 state, in man especially, the individual is educated and 

 fitted to discharge the duties of active life. Again, ana- 

 logous to the imago state is the age of puberty, in which 



* See on this subject N. Diet. a" Hist. Nat. xx. article Metamor- 

 phosis. 



