In addition to butterflies, I also saw a lot of dragonflies. I have no idea what species each of these are (comments are welcome). I have discovered that Dragonflies (who rest with their wings out to the sides) and Damselflies (who rest with their wings behind them) are members of the order Odonata, which means "toothed ones".
Update: I found a great site with lots of dragonfly plates and pictures that is helping me ID these creatures. See: http://public.fotki.com/gstrick3/. The first dragon fly appears to be a "Blue Corporal," Libellula deplanta.
I was able to get at least three (maybe 4) different species. This one (on the left) appears to be an Eastern Pondhawk. All of these are dragonflies. I did find a great site to provide an overview: "Odonata: Dragonflies and Damselflies".
This dragonfly to the right seems to have a "tiger striped" body.
And this last shot of a dark blue dragonfly looks like it's body is "furry" -- but it's hard to tell for sure.
If anyone can recommend a good book on Butterflies, Dragonflies and Damselflies for the Texas area, I would appreciate it. Texas is in an awkward spot between "East" and "West" as most wildlife books are divided into Eastern US and Western US, and it's hard to tell where we fall.