348 NATURAL THEOLOGY. 



into a black, hard, crustaceous beetle with gauze 

 wings. These, as I said, are astonishing processes, 

 and must require, as it should seem, a proportiona- 

 bly artificial apparatus. The hypothesis which ap- 

 pears to me most probable is, that, in the grub, 

 there exist at the same time three animals, one 

 within another, all nourished by the same diges- 

 tion, and by a communicating circulation, but 

 in different stages of maturity.'^^ The latest dis- 



^ The following observations do not exactly support the opinion 

 of Dr. Paley. It is more probable that the parts which are to ap- 

 pear in the perfect insect do not exist in the larvae, where there is 

 not much difference between the larva and pupa, excepting at the 

 time just previous to its becoming a pupa, at which time the larva 

 is motionless and torpid. The caterpillar of a moth, when about 

 to turn into a pupa, provides for the protection of the latter state, 

 either by surrounding itself with a web, or by some other means. 

 Soon after this is accomplished the caterpillar becomes motionless, 

 or nearly so ; it can neither eat nor crawl. At this time, and not 

 before, the parts of the pupa are forming within the skin of the 

 caterpillar, which may be easily seen by dissection. When the 

 difference between the larva and the perfect insect is great this is 

 always the case, and the pupa is passive; but when the difference 

 is not so considerable the case is different. The larva of a grass- 

 hopper scarcely differs from the perfect insect it is to become, ex- 

 cept in wanting wings ; the pupa differs only in having rudimen- 

 tary instead of perfect wings ; it casts its skin ; it is then the per- 

 fect insect, excepting that the wings are crippled, and these very 

 rapidly expand. In this latter case it is seen that there is but lit- 

 tle difference between the three stages, and the change from the 

 caterpillar to the moth is very great, and takes place only during 

 the torpid state of the former, which state is to allow of its taking 

 place, in the case of the grasshopper, where the changes are but 

 slio-ht, we should imagine but little of this torpidity would be re- 

 quired ; and such appears to be the case, for the pupae of grass- 

 hoppers, and allied insects, are always as active as either the larva 

 or perfect insect. 



