Abstract

                                Studies on the behaviour of organisms, and espe- cially on that of Insects, have formed the theme of many eminent zoologists in the past and yet there exist numerous points in the different aspects of the subject which offer avenues for further inves- tigations. The study of insect tropisms is one of these, and though a good deal of work has been done by eminent workers like, Loeb. Wheeler, Morgan and Jennings in the west, the study of the complex tropic reactions of insects in the Indian region has received hardly any serious attention so far. This paper is the result of some preliminary studies recently started to study the aspect of one of the various insect responses, viz., 'Phototropism' with special reference to South Indian insects, and indicate in what way it has an economic bearing on Agricultural Entomology. To an agriculturist the study of entomology is solely a utilitarian one, particularly with an aim to control his crop pests. Next to a knowledge of the life-history of the insect pests, the study of their behaviour, their adaptations and response to environments, and exter- nal stimuli forms one of the main lines of work for finding ways and means of control on scientific and economic lines.

Key words :