红尾追寄蝇是马尾松毛虫幼虫期的重要寄生天敌,主要寄生5～6龄松毛虫,第1、2、3代松毛虫寄生率分别为21.37. 44.95和0.71％。该蝇在湖南年发生5～6代,以蛹在土内越冬。95％以上的卵产于寄主胸足上,每寄主体上的着卵量为1～33粒,最多出蝇11头。当着卵量在7.5～20粒时,寄主陆续在幼虫和蛹期全部死亡;2.5粒时有3％的寄主仍能存活。寄蝇种群数量变动与当年5月气温成正相关,与7年下旬至8月上旬气温成负相关。 Red-tailed chase flies is an important parasitic natural enemies of Dendrolimus punctatus larvae, the main parasitic 5 ~ 6-year-old pine caterpillars, the first, second and third generations of Dendrolimus parasitica were 21.37. 44.95 and 0.71%. The flies occurred in Hunan in 5 to 6 generations, with pupa in the soil overwintering. More than 95% of the eggs produced on the host chest feet, each host on the amount of eggs for the 1 to 33, the largest flies 11. When the eggs were between 7.5 and 20 eggs, all the hosts died in larvae and pupae stage, and 3% of the hosts in 2.5 grains survived. The population change of fly flies was positively correlated with the temperature in May of that year, and negatively correlated with the temperature in late July to early August.