Abstract
The surveys on larval habitats of flies of medical importance were carried out on July 1957, at the residential quarter of Mitsubishi Kogyo Co. in Ashibetsu City, Hokkaido and the most important habitat of the larva, Fannia canicularis, the dominant species in houses of this district, was found in steeper of 'Takuwan', Japanese pickled garden radishes using rice-bran and salt as media. F. can. was found in steepers of 56 families and Muscina stabulans was found in 28 families out of 112. While, by the general surveys following species of fly larvae were collected.. Garbage box : Phaenicia sericata, Ophyra leucostoma, M. stabulans (these three species occupied the majority number of individuals), F. can., Sarcophaga peregrina and Lucilia illustris.; Lavatory : Calliphora lata, S. pereg., S. similis (those three showed majority number), F. can., F. scalaris and M. stab.; Pig-pen : M. stab. and Lucilidae sp.; Chicken house : F. can. and O. leuc.; Rabbit house : O. leuc.; Vegetable manure heap : Sarcophagidae sp.. Number of individuals collected from animal sheds was few. From the results obtained by the surveys in Ashibetsu, similar surveys on steepers were carried out at several districts in Hokkaido, Akita, Tokyo and Kanagawa on July, August for comparison. High popularized rate of 'Takuwan' was observed in rural and fishery villages than town district and high occurrence rate of F. can. was found in northern part of Japan than the south. The larvae found in Takuwan steepers were swarms of F. can. alone or mixture of F. can. and M. stab. and no swarm of M. stab. alone was found. The occurrences of the two species mentioned above differ by the conditions inside of steeper, i. e. M. stab. seems to like more water content in the media than F. can.. Although the most important habitat of F. can. larvae in Hokkaido is 'Takuwan' steeper, but habitats as lavatory and animal shed may have also importance in town district of Honshu and southern part of Japan. The control method for steeper was discussed in this paper, but the problems of other habitats and their control will be studied and discussed in the future.
