'As far as is known at present, atroparvus is the only A. maculipennis variety which will breed easily in the laboratory, so that there is no known reason to doubt but that we are dealing with the variety atroparvus. Along the south coast of England this variety greatly exceeds that of messeae; from a large series of ovipositions examined during the breeding season the ratio of var. atroparvus to var. messeae is about eighty to one. Some studies of the habits of Anopheles maculipennis over a period of ten years was described by me in “The journal of Tropical Medicine and Hygeine.”, (March 15th 1933), entitled “The Life History and Habits of British Mosquitoes in relation to their control by antilarval operations.” In describing the habits of A. maculipennis I suggested that this species was quite indifferent as to its source of food supply, whether it was oxen, horses, pigs, or man; that the chief factor was the construction of the building, that providing the necessary condition of food supply is fulfilled, the insects see to select the shelters which are dark and ill ventilated. At the time the above paper was written the races problem had not been studied but I have since made numerous collections and, as stated above, two varieties (atroparvus and messeae) have been identifies but atroporvus greatly outnumbers messeae.'