Giant Waxie Monkey Tree Frog Identification

[Lija]

Curious, what makes you think that it is a female.

males are smaller, they call, during breeding season develop nuptial pads and most importantly their head shape is different from females.
to illustrate i use sauvagii, same principle apply:

nuptial pads


head shape - note the line going down from nose to the chin, males have more developed chin, while females have less developed one and the line goes straight down

male:


female


see the difference? exactly same applies to bicolors