No, the employer cannot do this:1) Even though you should have had taxes taken out, the law is clear that an employer may not withhold or deduct money from pay without employee consent or agreement. Therefore, even if you do owe taxes from earlier checjks, he can't take it out of later checks. You may have to pay those taxes to the IRS at tax time, but that doesn't let him withhold the money now unless you were to agree to it.2) If you are paid on an hourly basis, you are not exempt from overtime and must get it under the law (e.g the FLSA or Fair Labor Standards Act) whenever you work more than 40 hours per week.Your employer appears to be violating the law. You may wish to contact the state department of labor about filing a complaint.