Employer forgot to pay me?

My job didn't pay me today! What should I say in my email?! I don't want it to be mean. I just want them to realize they didn't pay me today. I sent in my time sheet on time (have an email for proof) and I have direct deposit. Time sheets were due 2/17 with a pd of 2/24. There has never been an issue with my paycheck since I have been working there for 9 months. I live in CA btw. I'm not sure what the laws are for late paychecks...