There are 30 species in the genus Spodoptera Guenée, 1852 worldwide distributed, occurring mainly in the warm regions. Fifteen species are considered plagues feeding on several important agricultural crops as soybean, corn, rice and potato. The immature stages morphology of this genus is not well known. In about one third of the most economically relevant species, the caterpillar is not described and, also, few information related to the chrysalis and the eggs are available. Spodoptera cosmioides (Walker, 1858) is one of the most important pest among the noctuids occurring in Brazil with no information about its immature stages. Detailed morphological descriptions and illustrations of the immature stages of S. cosmioides, as micropilar area of the egg, chaetotaxy, spinneret, caterpillar ground color, arrangement of the appendages and natural openings of the pupa, are presented for the first time. Taxonomic remarks are also provided.
Caterpillar; chaetotaxy; egg; pupa; spinneret
