Abstract
This work is a continuation of that already published on the larvae of the Olethreutidae (now considered to be a subfamily, the Olethreutinae), and is to be used in association with the latter, since no larval characters as yet known separate the two subfamilies. Over 100 species of the North American Tortricinae are discussed, the late-instar larvae of 97 of these are described, and morphological characters of most of them illustrated. Many of them are well-known economic pests such as the spruce and pine budworms, the black-headed budworm, the omnivorous leaf tier, etc. Keys to tribes, genera, species groups and species are provided. The inadequacies of a taxonomic classification based solely upon adult characters are also demonstrated in an examination of the larvae of the genus Archips as presently established.