You see, flies, as with most insects, undergo a complete metamorphosis from egg to adult via a larvae and a pupal stage.

苍蝇，和大多数昆虫一样，经历幼虫和蛹的阶段，完成从卵到成虫的完全蜕变。

Now this is the pupal stage, and at this stage the females are larger than the males.

现在是蛹阶段，在这个阶段雌性比雄性大。