What is "cossina"

Cossina is the name for both a section and subsection of Ditrysian insects in order containing both butterflies and moths having a dorsal heart vessel. The section named cossina contains 2 subsections: one also named cossina (containing mostly smaller moths) having pupae with dorsal spines; and subsection Bombycina (containing generally larger sized moths and butterflies) having spineless pupae.