Chaetotaxy is the arrangement of macrochaetae (bristles ) on the body surface of insects. It is very important for determining homology in morphological traits, as well as providing information about the phylogeny between taxa. In case of Noctuide Lepidopteran Spodoptera mauritia thoracic body segments of last instar observe two ventral setae, two sub ventral setae, four dorsal setae, two subdorsal and two lateral setae while six microscopic setae. There are three punctures towards dorsal surface ( XDa, XDb and XDc).