I call him "Stan".
Yes, yes, I have heard the arguments against anthropomorphizing, especially with children, but, really, "Ctenucha" is such a mouthful.
So, Stan he is. Until he hatches anyway, and then he might just be "Stanette".
Maya found him yesterday clinging to the side of our plastic pool. It is the larvae ("caterpillar" or, as Maya says, "killerpatter") form of the Ctenucha virginica moth. We found our bug jar and the girls dug out their magnifying glasses and spent some good quality time investigating our new friend.