During 1913 a t Guelph, 1914 a t Orillia, and 1915 and 1919 a t T'ineland. the immature stages of many species of Syrphidz, but more especially the aphidophagous or aphid-eating forms, have been studied by the author. As t h e study of these flies is of considerable interest to the fruit grower and gardener. cnving to their beneficial habits, the observations made chieflv concern such spccies as were found to be of the greatest economic importance Species belonging to four genera, Syrphus,

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... rapta, Sphzrophoria, and Paragus have been especially studied with the view-of obtaining information as to their importance in the natural control of aphids injurious to farm crops.