HELP! Puppy & Dog not getting along!!!?

I have a one-year-old female Chihuahua who is sweet with people and can be a bit prissy. I recently got another Chihuahua, this time male, who is about 10 weeks old. He is loving, affectionate and very sweet. When he tries to play with her, she growls and bites him. It is very scary because I have seen her bite people before (including me & my fiancee) and her bites have even drawn blood. Should I let them play (with her biting him) or should I yell at her when she bites his face (which doesn't seem to stop her)??? Any advice is greatly appreciated!