Err, no, not thighhighs as they go all the way up to her waist. They're actually tights. From the thigh up, they're nude colored. Tagging both pantyhose and thighhighs sounds fine to me since they're mock thighhighs tights.
I've removed the pantyhose tag. Are you guys making the assumption that just because the real way to accomplish that type of appearance in the real world is through printing them on pantyhose? Because drawings don't usually care about what is and isn't possible in reality. Proof of point: post #2114614 (NSFW/loli).
edit: The colors of her skin and on her thigh are different, but I'm not sure if that is proof that she is wearing pantyhose. Color comparison. If you think that is enough to prove she's wearing pantyhose, then alright.
To me they just look like regular thighhighs with a cat shape, like in post #1604098 I might be wrong, though the difference in skin tone probably comes form the skirt's shadow.