354 ANNUAL OF SCIENTIFIC DISCOVERY. 



uniformity of their numbers each time, it appears that, from the liabil- 

 ities of destruction during the long term of seventeen years, out of 

 these 500 embryos only two appear certain of life and appearance in 

 their perfect state ; that is, just replacing the two parents. The 

 chances of life, therefore, with this insect, are, in round numbers, two 

 in five hundred. This calculation may seem strange to some, but, if 

 we reflect, it can scarcely be otherwise ; for, suppose the chances were 

 double, that is, four in five hundred, then we should have at each time 

 just double the numbers of their last time, which observation has 

 shown to be untrue, and which would augur much evil for the future 

 condition of the vegetable world in the localities of their appearance. 

 Even if their chances were three to five hundred, or half again the orig- 

 inal stock, agriculturists would quickly perceive the difference. To 

 sum up the matter, then, we have here an insect whose economy and 

 conditions of life are so unique that it is almost entirely isolated from 

 human destructive agencies, and which is obliged to deposit five hun- 

 dred chances for the certainty of securing two. The ovaries have 

 been formed with this capacity, and the whole internal economy is of 

 a corresponding character. 



From these data we can draw two valuable conclusions : 1st. The 

 evidence of design in Nature in thus balancing numbers against chances 

 of mortality for the preservation of the species. 2d. The plurality 

 origin of this species, instead of a single pair. In the first, such evi- 

 dence I regard as of the highest zoological character, and quite free 

 from many of those objections belonging to the analogous evidence 

 generally. As to the second, it is quite difficult to conceive how the 

 present myriads could have arisen from a pair, even if their chances of 

 life were increased twenty or thirty per cent., which we cannot believe 

 possible with the present climate of the earth. Regarding, then, these 

 insects, from these data, as of a special local creation, and whose orig- 

 inal numbers were nearly as great as at present, we find the same 

 view supported by different grounds. I refer to the fact of the differ- 

 ent years in which they make their appearance in different portions of 

 the _ country. Although, during the present year and the past ones, 

 indivisible by the number 17, have been those of its greatest appearance, 

 yet^the appearance of smaller numbers at different years has been 

 noticed in various or even in the same portions of country. In the 

 southern portion of New England, different parcels have appeared at 

 irregular periods ; and. in some of the Middle States, there are locali- 

 ties that have four distinct appearances of this insect. Now, as there 

 is no evidence for our thinking that they are ever unfaithful in their 

 time, appearing at the end of a longer or shorter interval than 17 years, 

 we are forced to the belief of not only their special local creations, but 

 special creations at different periods in the same locality. The ground 

 of such inferences is, I think, equally as tenable, as much as in geology 

 and_ paleontology, and certainly is in accordance with many of the rec- 

 ognized principles of zoological science. 



