Hyla cinerea is my vote too (I have an album for mine if you wan more comparison).

The burrowing could be humidity as mentioned, could also be fear of his new surroundings so time will be needed to settle in. Check out the care article http://www.frogforum.net/tree-frog-c...ysoscelis.html different frog but similar requirements (your frog isn't freeze tolerant). A home for him is 10 gallons minimum, more is always appreciated (mine lives in this for now, but will get a larger tank as he grows). Height is more important than width as they enjoy climbing. Lots of climbing and hiding spots. Avoid handling him if possible, they are look but don't touch pets.

Are you planning to keep him long term?