The adult stages of the two Heliothis species found most abundantly in the summer cropping areas of Australia (H. armigera and .H. punctigera) are easily distinguishable and have been so for some time. However the inability to distinguish the larval stages of these two species has hampered research on their ecology. For the past 5-10 years scientists studying.H. armigera and H, punctigera have found that in the early larval' stages Cuticle pigmentation separated the species. More recently hair colour differences on the last instar larvae have proved successful for identification. Verification and refinement of these techniques is presented