Abstract
Third instar larvae are described for the first time for the following species: Nicrophorus defodiens Mannerheim,N.guttula Motschulsky, N.hybridus Hatch and Angell, N.marginatus Fabricius, N.nigrita Mannerheim, N.obscurus Kirby,N.orbicollis Say and N.sayi Laporte, and are redescribed for N.investigator Zetterstedt, N.tomentosus Weber and Ptomascopus morio Kraatz. Keys are provided to larvae of the subfamilies of Silphidae, genera of Nicrophorinae and the known third instar larvae of Nearctic Nicrophorus.A subfamilial description of the larvae of the Nicrophorinae and a generic description of the larvae of Nicrophorus are presented. Evolutionary trends within the larvae of Nicrophorinae and phylogenetic relationships among Nearctic Nicrophorus are discussed.Larvae of Nicrophorus are very similar, differing horn Ptomascopus primarily in the reduced sclerotization and by possession of spines in place of the tergal lobes of the latter. This trend towards reduced sclerotization continues within Nicrophorus, with species groups being recognizable on the basis of the form and extent of the ventral abdominal sclerotization, positioning and sclerotization of the labial palpi and the presence or absence of sutures at the bases of the urogomphi.