Everybody now-a-days has books, even if he never reads them. It has become an acknowledged fashion—the more books the larger the wisdom, the finer the culture. The climax is reached in France, where you can buy as decoration for fine rooms large libraries, where all the prominent classic authors are represented only by the handsomely lettered backs of the volumes, stored in cabinets with glass doors. The key of the cabinets is invariably mislaid; in fact, the cabinets do not open at all. But even where book-cases contain real volumes, it is interesting to observe which authors are never taken out. In German private libraries, the binding of Klopstok's masterpiece, the Messiah, is almost invariably as fresh as possible, and in England and here I have often seen Paradise Lost in a very fine condition. As an instance of the contrary, when I was a young man, an older prominent naturalist singled out a volume from my library in a condition best to be described by book and binding in tatters, and then exclaimed, “That is just how I like to see books.” It was on bugs, and my scientific digestive organs were at that time in excellent condition. Later I was always interested in picking out books in similar condition in libraries, in order to have an idea of the taste and favorite studies of the patrons.

The following tables contain a partial resumé of the species common to Europe and North America, and also of what are technically known as representative species. I have intended to include only species which I have myself examined and which are with some certainty accurately compared. But the term “representative” species is in itself perfectly elastic, as I have elsewhere shown; in the present case the species compared are believed to have had a common ancestor in the Tertiary. With regard to the introduced species no historical data are accessible to me, and I doubt if any exist; it is a case for the operation of reasonable surmise. I think these tables are of preliminary interest and value; I first commenced to publish similar observations in the Bulletin of the Buffalo Society of Natural Sciences. In a comparison of European and American species we are chiefly indebted to M. Gueneè and Dr. Speyer.