Okay, so I found this key at work for determining Podisus nymphs. It's located here
In order to test and see if this key can be used to move a bunch of these Podisus nymphs we have, I'm going to carry out a little experiment and would LOVE to have other people join in on the fun. I'll be collecting as many Podisus nymphs from the field as I possibly can and photographing and keying them out according to the key I've provided. I'll raise each nymph to adulthood, and we'll see how reliable the key is. The earlier the instar of the nymph, the better. (This one is already a 5th instar).
This one, unfortunately keys out to the super-common Podisus maculiventris, and I suspect that's probably what it will be. I'm greatly hoping that I can get some other species of Podisus to try this out on.
Forum topic here