Abstract: Objective To find out peak day and peak periods of the seasonal change in numbers of flies, so as to work out a scientific plan for controlling and preventing the flies. Methods The circular distribution method was used to analyze the data collected from years of 2003-2004 in Shaoxing urban areas to monitor change in numbers of flies. Results It was showed that in Shaoxing urban areas, the peak day of seasonal change of flies was August 4^th during the years of 2003-2004; but it was August 11^th in 2003, July 29^th in 2004. The peak period of seasonal change of flies was from June 8^th to September 30^th during the years of 2003-2004, however, in the single year, it was from June 17^th to October 5^th in 2003, from June 1st to September 26th in 2004. Conclusion The change in numbers of flies has an obvious seasonal feature during the years of 2003-2004 in Shaoxing urban areas.

摘要： 目的 确定蝇类季节消长的高峰日和高峰时段,为制定蝇类防制措施提供科学依据。方法 用圆形分布法统计分析绍兴市区2003-2004年蝇类密度监测数据。结果 绍兴市区2003-2004年蝇类平均密度高峰日为8月4日,高峰时段为6月8日至9月30日。其中2003年蝇类密度高峰日为8月11日,高峰时段为6月17日至10月5日;2004年蝇类密度高峰日为7月29日,高峰时段为6月1日至9月26日。结论 绍兴市区2年中蝇类消长有明显的季节性规律。

关键词: 圆形分布法, 蝇类, 季节消长