What is my employer's legal obligation to my missing paycheck?

i originally was supposed to receive my paycheck for may 1st-15th in the mail, but have not received it. i have asked my employer about it quite a few times but get a different answer every time. now she's saying all she can do is give me a loan until the original check returns to her, which doesnt sound right to me. im wondering, by law, what is her obligation to my check that i have yet to receive?