In a study in The Gambia, West Africa, it was found that 96.2% of Anopheles melas Theobald and 91.59% of An. gambiae s. s. occurring sympatrically and in the absence of the other sibling species of the An. gambiae complex could be correctly identified using the palpal ratios. All ratios of 0.81 and above were ascribed to An. melas and all below to An. gambiae s. s. Up to 42% of An. melas had 4 pale palpal bands whereas all An. gambiae scored were 3-banded.