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Published online by Cambridge University Press: 31 May 2012
Richards (1955) detected insects in flight while studying changes in the amount of radiant energy from the sun. His report stimulated our consideration of a method specificallv intended to record insect flight activity. We wished, by means of a prtabic and relativelv simple apparatus, to detect and count insects flying throush a given space. The method developed differs somewhat in principle from that of Richards. In his apparatus the effect of an insect was to decrease slightly a large amount of energy continually falling on a photoelectric cell. Our method utilizes light reflected from an insect to a photoelectric cell which otherwise views a black background.