An important question is the area of origin of these spring immigrants. Over the last 3 years, we have been investigating the ecology of Heliothis spp. in inland Australia (Gregg et al. 1987, 1989). The most recent findings of this work are summarised by G. Fitt et al.in these Proceedings. Large populations of H. punctigera, and smaller but still significant populations of H. armigera, have been found over vast areas. They breed on native annual plants in winter. These plants dry off rapidly in spring, and the Heliothis disappear. This paper presents evidence which indicates that in 1989 they emigrated from the inland, and that significant nunbers arrived in the cotton areas of northern N.S.W. and southern Queensland.