This says the male clip goes to the female clip on the negative pigtail
http://www.wegosolar.com/products.php?product=MC%252dMALE-MC%252d4-Male-Clip-with-PinBUT--I would definitely use my voltmeter on the panel pigtails with the panel in the sunlight to be sure. If meter pos is on panel pos, the voltage shows pos, if reversed the voltage has a minus sign ( - )in front of it on the meter's readout.
This is the female clip that connects to the panel's pos male clip it says.
http://www.wegosolar.com/products.php?product=MC%252dFEMALE-MC%252d4-Female-Clip-with-PinYour panel's male clip is marked red, so that all checks out.
