They make eye contact and draw attention to themselves, but it is up to the male to make the approach and say the first word.

This author--Friar Wall
of The Monastery distinguishes between passivity and "proceptivity", which is described as common female flirting behavior.; there may also be useful discussion at this site, but I can't verify that, as I have been unsuccessful connecting to it so far.

Desmond Morris gives his summary here.