[[p. 5]] Butterflies: their Structure, Changes, and Life-Histories, with Special Reference to American Forms. Being an Application of the "Doctrine of Descent" to the Study of Butterflies. With an Appendix of Practical Instructions. By Samuel H. Scudder. (New York: Henry Holt and Company, 1881.)

     Mr. Scudder's great reputation as an entomologist will cause many readers to turn to this beautifully got up volume with eager curiosity. They will expect to find a tolerably full account of all those interesting and complex phenomena of metamorphosis, variation, dimorphism and polymorphism, protective colouration, mimicry, and distribution, for the elucidation of which no class of organisms offers such abundant and striking materials; while they might not unreasonably anticipate that the bearing of the whole series of these phenomena on the "Doctrine of Descent" would be clearly indicated and the necessary conclusions to be drawn from them strongly insisted upon. The first separate work ever published on the general history of butterflies, as distinguished from their classification or specific description, would naturally excite some such expectations as these; but those who have entertained such ideas will be disappointed, and may perhaps be inclined to give the book less credit than it really deserves. We will therefore briefly indicate its contents and point out a few of its merits and deficiencies.

     The first four chapters--"The Egg," "The Catterpillar," "The Chrysalis," and "The Butterfly"--respectively, give a very good general account of the form and structure of the insect during the stages of its existence, and they are illustrated by a large number of very excellent woodcuts, many of which seem to be original. Then follow descriptions of the internal organs, and their transformations during development, and a good chapter on habits, illustrated almost exclusively from North American species. We now come to the more important and interesting part of the volume, and find chapters on "Seasonal Changes and Histories," "The Colouring of Butterflies," "Diversity of the Sexes in Colouring and Structure," "The Origin and Development of Ornamentation," "Ancestry and Classification," and "Geographical Distribution," the titles of which cover a wide range, and seem to include all the chief points required for a full exposition of the subject. The treatment however is by no means satisfactory, since it is a rare thing to find any fact even alluded to beyond the range of North American species; and though the valuable observations of Edwards and Riley are frequently referred to, the important researches of Weismann and Fritz Müller are hardly mentioned. Far more important however is the almost total silence on the whole question of protective and warning colouration in larva and perfect insects and the wonderful phenomena of mimicry, which play so large a part in determining both the forms and colours of insects all over the world, and which are so marvellously developed in butterflies. The absence of all these considerations renders the chapter on "The Origin and Development of Ornamentation" most unsatisfactory, since it is almost wholly devoted to suggestions as to the probable lines which have been followed in the development of the ornamentation, while we are left without any clue to the reasons for such special and wonderfully diversified results, or the laws by which they have been produced. Equally meagre is the chapter on "Geographical Distribution," which is treated solely from the point of view of the North American collector.

     A more important fault than these deficiencies, in a work presumably intended for popular reading and to excite young American entomologists to a more complete study of their subject, is the very peculiar system of nomenclature adopted by the author, which, by the needless difficulties it will cause, must tend to disgust beginners with the whole study of natural history. The writer who has done more than any other person to facilitate the study of North American butterflies is Mr. William H. Edwards, who, besides a great work on "The Butterflies of North America," illustrated by fine coloured plates, has published, so recently as 1877, a complete "Catalogue" of the species. He is in fact the authority on North American butterflies, to the conscientious study of which he has devoted his life. When any such standard systematic work exists in a country, it seems to us the obvious duty of all who write popular books to follow its classification and nomenclature, not as endorsing their correctness, but simply to facilitate reference to works which every student must constantly refer to. Instead of doing so Mr. Scudder follows a quite different order in his systematic list of species, adopts a complex system of families, sub-families, tribes, and genera, mostly with unfamiliar names; and uses a generic nomenclature so totally unlike that of the above-named standard work, that out of a list of fifty-eight genera referred to in his volume only ten have the same names as those adopted by Mr. Edwards. As an example of the difficulty and confusion this must cause to a beginner we may mention that the North American species of the old genus Papilio are here given under five distinct generic names: Lycæna under the same number, and Argynnis under four. The family Papilionides, which Mr. Scudder retains, no longer contains the genus Papilio, after which it is named, because he transfers this name to our old friend the Camberwell Beauty, which he styles Papilio Antiopa. The old Satyridæ, or Meadow Browns, are now named Creades, and they are placed at the head of all the butterflies instead of near the end, as in the works of Edwards and of all the old writers. This must be all the more puzzling, because throughout the body of the work these names are everywhere given without the least indication that they are not in universal use. Thus at pages 100-102 we have Basilarchia Archippus many times mentioned, with a reference to Riley. But that author always uses the old name Limenitis disippus, and in the copious index to his Missouri Entomological Report, just issued, the name Basilarchia is not to be found, neither does it appear, even as a synonym, in Mr. Edwards' "Catalogue"! No one will object to differences of opinion on questions of nomenclature, when kept to their proper place in strictly scientific treatises; but every one who has at heart the extension of a taste for natural history has a right to protest against such totally unnecessary difficulties being thrown in the path of beginners.

     We regret having to speak so strongly in animadversion of a book which contains much interesting matter and much valuable information, which is written in a pleasant [[p. 6]] style and is illustrated in a very attractive manner. But we feel that an opportunity has been missed of producing a volume which should open up one of the most marvellous pages in the book of nature, in a manner to interest a wide class of readers and attract many new votaries to the study of these most beautiful and in many respects most instructive members of the great class of insects.