The present war has brought to the fore the importance of malaria and other arthropod-borne diseases as military and home-front hazards. As a result there are probably more individuals directly concerned with the control of mosquitoes in this country and the world over than at any other time in history. It is particularly fortunate, therefore, that Doctor Matheson, Professor of Entomology at Cornell University, has produced a new, revised and enlarged edition of his authoritative “Handbook of the Mosquitoes of North America,” which, since its original appearance in 1929, has been a valued guide to students of this branch of entomology. While the literature on North American mosquitoes is formidable in bulk and rich in detail, monographic works of continental scope have been few and long outstripped by rapid advances in knowledge. Here, in this slim volume of 314 pages, is condensed the fruits of many years of patient labor in the form of a convenient handbook that is essential equipment for mosquito-workers in the United States and Canada.