These observations, dealing with noctuid larvae, were made while the writer was associated with the Canadian Forest Insect and Disease Survey. Twenty-four species have been examined: 9 in the Hadeninae, 10 in the Cucullinae, 3 in the Amphipyrinae, and 2 in the Catocalinae. The arrangement of the subfamilies follows that of McDunnough (1938). This material is being published because many of these species have not been included in Crumb (1956) and new data are presented on the species considered by him. The descriptions were made from living and preserved larvae. Notes on biologies, unless otherwise indicated, refer to those made by the writer in Manitoba and Alberta during the years 1944-1954. The hosts are those on which larvae have been reared to adults by the Forest Insect and Disease Survey, except in a few cases where the host is cited from the literature. “Free-living larvae”, are those that feed openly. When the number of instars is not known the larvae are described as antepenultimate, penultimate, and ultimate. In measurements, H.W. refers to head width, B.L., to total larval length, and B.W., to greatest larval width.