This beneficial insect is a problem in Christmas trees. The mantis leave an egg case that will hatch when the weather warms. If taken into a warm home they think it's spring and little insects can hatch out. We need them in the fields to control other destructive insects. After the tree is cut, we mechanically shake and inspect each cut tree for egg cases. They're removed and later deposited in our other trees for next year. The mantis deposits the egg case on the outer foliage, so they're not hard to find. We also, ask our customers to look for and remove any egg cases that we miss.