The kids and I have been trying to hatch praying mantis. We ordered the egg case and set up a habitat - and have since waited about three weeks. Finally, we saw that they had hatched and we were so excited. The only wierd thing was that only a few seemed to have hatched and about five or so seemed to have died and turned brown. One was still doing ok for awhile, and we released the wingless fuitflies into the habitat. The little guy is hard to find now, and I am wondering if he has died as well. I haven't found any research to suggest that they would have more than one hatching period. A science teacher told me that it might be that the temperature in my home is too warm, or that they had too much direct sunlight.