"For during many successive generations each individual beetle which flew least, either from its wings having been ever so little less perfectly developed, or from indolent habit, will have had the best chance of surviving from not having been blown out to sea; and on the other hand those beetles which most readily took to flight would oftenest be blown out to sea and perish."[371] So apt are we to believe what we are told, when it is told us gravely and with authority, and when there is no statement at hand to contradict it, that we fail to see that Mr. Darwin is all the time really attributing the winglessness of the Madeira beetles either to the _qua_ him _unknown causes_ which have led to the "ever so little less perfect development of wing" on the part of the beetles that leave offspring--that is to say, is admitting that he can give no account of the matter--or else to the "indolent habit" of the parent beetles which has led them to disuse their wings, and hence gradually to lose them--which is neither more nor less than the "erroneous grounds of opinion," and "well-known doctrine" of Lamarck. For Mr. Darwin cannot mean that the fact of some beetles being blown out to sea is the most important means whereby certain other beetles come to have smaller wings--that the Madeira beetles in fact come to have smaller wings mainly because their large winged uncles and aunts--go away. But if he does not mean this, what becomes of natural selection? For in this case we are left exactly where Lamarck left us, and must hold that such beetles as have smaller wings have them because the conditions of life or "circumstances" in which their parents were placed, rendered it inconvenient to them to fly, and thus led them to leave off using their wings. Granted, that if there had been nothing to take unmodified beetles away, there would have been less room and scope for the modified beetles; also that unmodified beetles would have intermixed with the modified, and impeded the prevalence of the modification. But anything else than such removal of unmodified individuals would be contrary to our hypothesis. The very essence of conditions of existence is that there _shall be_ something to take away those which do not comply with the conditions; if there is nothing to render such and such a course a _sine qua non_ for life, there is no condition of existence in respect of this course, and no modification according to Lamarck could follow, as there would be no changed distribution of use. I think that if I were to leave this matter here I should have said enough to make the reader feel that Lamarck's system is direct, intelligible and sufficient--while Mr. Darwin's is confused and confusing. I may however quote Mr. Darwin himself as throwing his theory about the Madeira beetles on one side in a later passage, for he writes:--