My b2evolution Version: 4.0.3

http://wccoa.org/index.php/Nutrition/mealsonwheels/signup/

I'm trying to get the field that says "Meals on Wheels Signup" at the bottom to be invisible. I want the field info passed to my form (to populate the Subject line in the email that gets sent) but I don't want it to appear on the page. Can someone tell me how to do this?