 Where possible, the yellow should be the same width as the blue, but on Spitfires with their narrower fuselages a thinner ring was acceptable.Also in May, an order was made to put red, white, and blue roundels on the underwings of all fighters, with an addendum that where the roundel was on a black background it should be outlined in yellow.In June, orders were given for the half black/half-white underwing scheme to be replaced by "sky" Underwing roundels were dispensed with until August when they were ordered back.