“There are no satisfactory distinctions between some of the moths which enable any one to say that they are of such and such species, and very frequently they are separated into different kinds because they happen to feed on various plants, and because the moths are not all colored in the same manner. Of course the Entomologists that believe in the real nature of species have taken a vast deal of trouble with the Noctuina, but those who do not think a species to be anything more than an abstract idea, and that it really consists of the sum of the variations of a closely allied series of forms, do not see the use of this Natural History hair splitting.”