Was she eaten?

[UncleChester]

If possible, get someone else to search the tank.

I would also remove the larger one to a temporary tank at this point. It will be easier to monitor the tank for changes made by the little frog if it's still alive and in case the little one hasn't been eaten but is small enough to be eaten, it will prevent any future problems. Also check the contents of any fecal matter that the big one produces, I'd expect bones might make their way through.

Hyla cinerea don't have a big reputation as cannibals, but it does apparently happen. There is a report of a 40mm frog eating a 20mm one and then regurgitating the little one after it was handled. You can read about it in this link but be warned it includes the disturbing picture of the event occuring https://pantherfile.uwm.edu/hoebel/w...42(1)85-86.pdf

[maxQ]

I went through the same thing, I swore my male got out, I used a flash light and magnify glass and I finally located him just hanging out between two rocks. Good Luck