Dr. L. O. Howard, the entomologist of the United States Department of Agriculture, has just published a bulletin entitled, “Notes on the Mosquitoes of the United States: Giving some Account of their Structure and Biology, with Remarks on Remedies.” The author has, for some years, been interested in the general subject of the biology of mosquitoes and of remedies to be used against them, and has brought together in this bulletin all the published and unpublished notes which he has been collecting during this period. The bulletin contains synoptic tables of all North American mosquitoes, prepared by Mr. D. W. Coquillett, and gives detailed facts regarding the geographical distribution of the different species mentioned. All the five North American genera are illustrated and full, illustrated accounts are given of the life history of the two principal genera, Culex and Anopheles, as studied in _Culex pungens_ and _Anopheles quadrimaculatus_. The author calls special attention to the two genera of large mosquitoes, Psorophora and Megarhinus, and urges the importance of the study of these two genera, especially by physicians in the South, in regard to their possible relation to the spread of malaria. Considerable space is given to the subject of remedies, the principal ones considered being kerosene on breeding pools, the introduction of fish in fishless ponds, the artificial agitation of water and general community work. It is clearly shown not only that the mosquito may be, in many localities, readily done away with at comparatively slight expense, but that by careful work many malarious localities may be made healthy. The subject of mosquitoes and malaria is not discussed in the bulletin, which contains simply references to available papers on this subject, like the article by Dr. Patrick Manson, published in THE POPULAR SCIENCE MONTHLY for July, the aim of the author being to bring together all available facts about the mosquitoes of the United States, in order to assist physicians who are studying the malarial relation from the point of view of local conditions. THE PROGRESS OF SCIENCE.