Protesilaus glaucolaus is a species of butterfly found in the Neotropical realm In order to differentiate this and the following species [molops] with certainty, it is necessary to compare specimens from the same districts, and at times to take the sexual organs into consideration.

In glaucolaus the black postdiscal band of the forewing is widely separated from the lower angle of the cell, or the teeth of the hindwing are very obtuse and the posterior submarginal spots suffused with brown.

leucas R.& J. Wings only distinctly green towards the base; postdiscal band of the forewing narrowed near the lower angle of the cell and usually before the 2. radial.

Hindwing more obtusely dentate than in protesilaus, the submarginal spots tinged with brown, 2. band of the forewing from the cell backwards narrower above than beneath, the side of the frons white.

The harpe of leucas more obtuse than in glaucolaus, the dorsal tooth narrower and the central process longer.