Here's a sample of the package that I got from an exchange with some forum members. Sorry for the blurry pics. You can buy Mason bees either as cocoons or in straws. If you got them in straws, I recommend that you open them, clean them up of other insects that may be hitchhiking and separate the cocoons. The best time to get the Mason Bee cocoons is during the winter season so that they can be shipped without hatching along the way. You can store them in the crisper bin of your fridge for as long as it takes you to build their houses, but don't forget them or they will die if left long enough, or when they hatch, there are no more flowers for them to feed on.