THIS attractively printed manual, notwithstanding its title, is not a general book on ectoparasites, but a guide to the study of certain economically important groups. Its author, Dr. H. E. Ewing, is a well-known member of the United States Bureau of Entomology, and in preparing this book he has been able to draw upon the extremely complete collections of the creatures he deals with that are contained in the National Museum at Washington. The first five chapters are devoted respectively to mites, ticks, biting lice, sucking lice, and fleas. Each of these sections contains keys to the families and genera, together with some considerations of the external anatomy, economy, and control measures, while representative species are shown in the illustrations. At the end of each chapter is a list of the more important literature on the subject concerned: the references are well chosen, and by no means confined to American writers. The sixth and final chapter takes the form of an appendix containing descriptions of a number of new genera of ectoparasites. The wisdom of this procedure is disputable, but, it may be added, the new genera described are included in the keys given in the foregoing sections.
A Manual of External Parasites.
By Dr. H. E. Ewing. Pp. xiv + 225. (London: Baillière, Tindall and Cox, 1929.) 20s. net.