Theoretical scenario question I came up with. Unrelated to anything, just a weird idea.
A humanoid species has evolved to appear to humans to be a human female. In fact they have bat-like wings which fold up on their back (which they can use to fly) and a medium-length scaled tail barbed with a strong toxin. It attracts human males, gets them on their own, then kills them using their tails. It needs to eat one fully-grown human male approximately once every two days to survive.
Problem: The race consists solely of females, and they can't be fertilised by human males. Even if they could, pregnancy in a human way would probably put off many males for far too long. And the child either needs to be born old enough to attract males to eat or the mother has to supply extra food, which would be very difficult likely as not.
How can they reproduce?