Page:The Indian Journal of Medical Research, 1920.djvu/104

 A SURVEY OF THE CULICID^ OF A RUBBER ESTATE. BY R. A. SENIOR-WHITE, f.e.s. [Received for publication, July 5, 1920.] During a period of one year, from March, 1919 to February, 1920, T have had under observation the breeding places of mosquitos on Suduganga Estate, Matale District, Central Province, Ceylon, the results of which are incorporated in this paper. The planting district of Matale consists of a valley enclosed between the north-eastern and north-western blocks of the main mountain miss of the Island,^ the distance between the summits of the two ranges being about ten miles. The valley thus enclosed contains a series of ridges, longitudinal earth-folds lying parallel to the main ranges some of the summits of which are raised above the floor of the valley by as much as 1,200 fc. The floor of the valley, which is drained by the Suduganga river, is slightly over 1,000 ft. above sea-level, — the highest summits on the enclosing ranges exceeding 4,000 ft. Suduganga Estate stretches across both sides of one of these folds — the western boundary being the river, a perrcnnial stream here flowing betwean low banks in a sandy bed, liabl • to sudden floods during periods of heivy rainfall during both monsoons. The annual rainfall varies from 'lO to 100 inches. Though the elevation of the river-bed here is only slightly over 1,000 ft., the highest point on the ridge running through the Estate reaches 1,628 ft., the rise being accomplished in a direct distance only slightly exceeding a quarter of a mile. A similar ridge rises steeply from the western ])ank. ( ii04 )