Morphological variations in larvae of Syncirsodes primata (Walker 1862) from different hosts were studied. Three different morphs, varying in the number of dorsal tubercles and color, were detected. It appears that these variations depend upon the species of host plant on which the larvae inhabit. The results suggest that the selection of host plants may determine the color, indicating phenotypic plasticity. However, constancy in tubercle number, independent of a change of host plant, suggests genetic differences among morphs