The Measurement and Control of atmospheric Humidity in relation to Entomological Problems

Abstract

It is a matter of general agreement that atmospheric humidity is often of great importance in limiting the times or places at which insects are abundant. But though one may collect facts which suggest that a particular degree of dryness or dampness favours some stage of an insect, it is not easy to devise experiments which will give unassailable facts. Some of us feel that the precise study of water relations and water balance may lead to greatly increased knowledge of the living insect, and therefore to results of economic value ; and it is certain that a fuller understanding of these matters is delayed because few know the methods appropriate for measuring and controlling humidity. The purpose of the present paper is to make known a number of practical methods, which might be of service to a worker even in a remote country. As this is my objective, I shall include material which is already well known to physicists, and as our concern is with the conditions in the places where insects are actually living, I have given particular attention to unorthodox devices which can be used in small spaces and which are portable; among the great variety of methods, I have endeavoured to show what is good and bad in each.