goto you local high school and talk to science teach or earth science teacher and see if they are doing a unit on genetics... common part of the lesson plan is a house fly or fruitfly breeding project, if they arent currently doing anything then have your parents order you a culture online. If you have nymphs now and arent prepaired to care for them you may have just learned a valuable lesson in prepairedness. Other then that if its warm where you live then you may very well be able to collect something outdoors which is suitable... I dont know where you live so its hard to direct you to something...
If you still need to get fruit flies, high schools are often teaching with fruit flies at this time of the year, as was mentioned earlier. You could also call a Biology Dept at a local university or college. That is how I found some of my fruit flies when I needed them quickly. Hope this helps.
I posted some links in another thread where you can order the flies. They can eat pinhead crickets but the crickets will stay down at the bottom and the mantis will probably stay up top.
I dont think that a hatchling carolina would be able to take a pinhead. When my S. Limbata hatched they were able to take fruitflies great, but there is no way one would be able to take a pinhead. I dont know for sure since I have never raised S. Carolina, but I cant imagine that S. Carolina and S. Limbata would be too much different when they hatch out.
Get some Meal Worms, wait 2 or so weeks till they pupay, and after a few weeks you will see little meal worms which are a great sorce of protein for the nymph mantids.
If you can't do that get some where some flightless or wingless fruit flys, and keep them on this media which you can make...
8 cups potato flakes 1 cup powdered sugar 1/2 cup brewers yeast. The potato seems to make the fruit flys grow twice as fast unlike the blue stuff petshops use.
I don't think mealworms are a good food for em. The flies are really easy. Only bad thing about pinheads is that the mantis has to go to the bottom to get em. Mine learned it pretty quick.