In this laborious work the author of a useful little Manual of European Butterflies gives a list of all the species of Butterflies described up to the date of publication, with references to all the chief authorities and the various names under which each has been described or referred to. The native country of every species is also given, thus affording valuable materials for the study of geographical distribution. The general reader will be surprised to learn that this list of the names of butterflies forms an octavo volume of 690 pages, there being more than nine thousand described species and varieties of butterflies; and as many of the specific names occur several times over, the index, which consists of 130 columns of very close print, contains about twelve thousand separate references. When we consider that this volume contains only the true butterflies (the moths being many times more numerous), some idea may be formed of the immensity of the range of the entomologist's studies. The value of such a work to students is very great, while the labour of compiling it is of the most thankless and unremunerative kind; and although some faults of place and of detail could be pointed out, it would be ungracious as it is unnecessary to refer to them here. The work is published by Mr. Van Voorst, and every naturalist who can afford it should add it to his library, not only for its intrinsic value, but as a recognition of the service bestowed on science by its painstaking author.

A. R. Wallace.