eco friendly bug control

we ordered 2 pods of praying mantis eggs from some online nursery and have been waiting for them to hatch. the instructions said to place them in a paper bag with a stick or two, close the bag with a paper clip and then put in a window sill. it took about 2 weeks and then a few days ago jeff opened the bag to check on their progress and they had hatched! so outside they went. we tore the bag in half and then placed the bag on a plant and let them find their way out. these little praying mantis's were about the size of my thumb nail!
i have a terrible aphid problem, so we ordered these praying mantis's and some ladybugs in hopes that they would eat up all the aphids. i think most of my lady bugs flew off!