Abstract
Insects belonging to the genera Bradina, Cnaphalocrocis and Marasmia (Lepidoptera: Pyraustidae) are generally pests of various graminaceous crops. The general appearance and shared behavioural habits of the larvae and adults render recognition of the various species difficult. In order to facilitate correct identification of species found in Kerala, the authors have devised an indentification key using morphological characters of their external genitalia