Observations On The Bionomics Of Anopheles

Abstract

The striking recedence of malaria in certain portions of the world and its equally noticeable extension in others are still in part unexplained phenomena, and offer a field for investigation that involves a consideration of many strictly biological problems. Viewed in its broader aspects, the successful conduct of a campaign against malaria rests upon a proper comprehension of the relation of three organisms belonging to widely separated groups of the animal kingdom. The importance of understanding the biological or ecological features of the problem can hardly be overestimated. The possible existence of natural causes favoring or hindering malaria is a matter upon which studies in the field may be able to shed light. An instance of the fruitful outcome of general observations is found in Theobald Smith's1 suggestive remarks on the natural history and probable mode of spread of tertian malaria in Massachusetts. With these points in mind the writers have undertaken a series of detailed observations on the bionomics of the malaria-bearing mosquito. The following observations on Anopheles have been carried out partly in the vicinity of Chicago, partly in a small country town in western Michigan (Eastmanville, about twenty miles west of Grand Rapids), and partly in a locality in New Hampshire (Shelburne) already described by one of the writers.2 Anopheles larvae were collected at thirty-four different points in and about Chicago, including thirteen stations within the city limits. Breeding pools were found in all quarters of the city, and in the suburbs on the north, west, and south sides. The adult mosquitoes sometimes invade rather thickly settled parts of the city, and have been captured in houses within two blocks of