volumes in the future, in the determination of genera and species, and the demarcation of families, will carry very largely the classification along at the same time.
This classification is distinctly based on evolutionary principles, depending almost entirely on wing structure. The author, as an evolutionist, makes himself clear. "The present families and genera are not of course derived from other existing ones, but from their ancestors; and when a family or genus is said to be derived from another, all that is meant is, that in order to reach their present stage of specialization, their ancestors must have passed through a stage which would in essential points of structure come within the definition of the other family or genus. And as a corollary, the plan of the book is "to begin with the most highly specialized families, genera, and species, and gradually work down to the most generalized forms."
The Syntomidæ, as treated in this volume, number 1184 actually described species, of which a very large proportion indeed is figured, generic characters pourtrayed, and full synonymy given. The last does not represent the mere useless occupation of a specialist as some theoretical writers incline to stigmatize. A zoologist is supposed to know the animal kingdom and its members under one and not various names. This promiscuity is not altogether unavoidable by workers residing in different centres of activity, and of course absent from one general collection of types. To assist this work, material has been lent and given from all sides, which, added to the immense and almost unique Heteroceral wealth now contained in the British Museum and in private collections in the country, makes the specific verdict of this volume one likely to provoke little "appeal." These books mark a very prominent aspect of our age in all departments. "The rich are getting richer"; in commerce the large undertakings are swallowing up the smaller ones; everywhere we see centralization as a necessity exerting its sway; and so in the technical zoology of the future it will be understood that only large national collections worked by State aid can give the last words in the zoological nomenclature which will be accepted as a canon, and liberate naturalists for other work. If we compare this and other catalogues with the encyclopædic work
