I was pretty desperate for flies when I got them from Rebecca, with it being winter here and all. The pupae from her hatched within 3 days of arriving, right now at about a 25% hatch rate but that's because I am refrigerating them for the most part and hatching when I need some more (I bought 500 pupae and a bottle of house fly food). When it gets warmer I am definitely going to make a bug catcher to make things interesting for my mantids. Maybe something like these 2