144 On the Caterpillar which 



When there are but two genera of an animal, and I 

 determine the animal not to be of the one genus, I am 

 understood by every ingenuous man, who has proper 

 authorities before him, to place the animal in the other. 

 A negative in this is fully equivalent to an affirmative ; 

 and I do not know that it is not the more elegant mode 

 of expression. 



In addition to the above, it might be remarked that, 

 in the following sentence of the letter, my opinion and 

 meaning must be placed without the limits of doubt. 

 " This genus so nearly resembles the real Caterpillar, 

 in figure and general appearance, as to be frequently, 

 while in its reptile state, taken for the genuine Cater- 

 pillar." That its reptile is here put in contradistinction 

 to its winged state needs no demonstration. In the 

 aurelia state there is doubt and uncertainty. Nothing 

 interpretative of its being true or false can be collected 

 from this state. Hence the necessity of its becoming a 

 winged animal ; or how could I, or any Naturalist, intel- 

 ligibly speak of a true and bastard genus ? 



Were it necessary to dilate more on this uninteresting- 

 point, I might subjoin, that, within my knowledge, 

 there is no animal doomed to exchange, in its aurelia 

 state, life for death. This state, from, I believe, every 

 authority, may be considered as the cradle of the winged 

 insect, but has never been found to be the coffin of the 

 reptile, except from accident. 



Thus much I have thought it necessary to say in il- 

 lustration of sentiments, which, from misapprehension, 



