PM me you email addy and I will scan and email you the actual key. It covers all the native and adventive mantids in the USA. That includes 5 species of Stegmomantis; S. floridensis, S. carolina, S. limbata, S. californica, and S. gracilipes.
THere is a good link with keys for identifying local species performed by Florida University. It has however only keys for S. Carolina and S. Floridensis. But also many good keys for local species you could use in your coming bug show Rick.
Larger (58mm or more); form more elongate, abdomen of female nearly parallel-sided, tegmina narrower, reaching only middle of abdomen; stigmatic patch pale, inconspicuous, or obsolete = Stagmomantis floridensis Davis
Smaller (57mm or less); form less elongate, abdomen of female strongly widened at middle, tegmina broad, reaching apical third of abdomen; stigmatic patch black, conspicuous (cover photo) = Stagmomantis carolina (Johannson)