During the winter of 1931-32, iny attention was drawn to the swarms of long-legged flies in a root-house attached to the barn on my father's farm at Salmon Arm, B.C. The root-house is built above ground, with sawdust insulation between the double walls, and has three ventilation shafts through the ceiling, and one at ground level; the floor is of earth, on which planks are put down as required. At the timle in question it contained a bin each of mangels and potatoes, about 200 boxes of unpacked apples, and sundry cabbages and carrots.