The type material in the Coleoptera Section of the Canadian National Collection is catalogued. The collection contains 679 holotypes, 355 allotypes, 47 lectotypes, 2 neotypes, 211 species are represented by syntypes, and 1392 by paratypes or paralectotypes. The reference to the original description for each species is cited. All data associated with the specimens is quoted except in the case of paratypes and paralectotypes. An index to all species is included.

The 33 species of Prosimulium Roubaud known from Canada and Alaska are reviewed. These are segregated into four subgenera: Distosimulium new subgenus, containing one species; Parahelodon new subgenus, containing three species; Helodon Enderlein, containing seven species of which clavatum, martini, and susanae are new, and one (known only from the larva) remains undescribed; Prosimulium s. str., containing 25 species of which approximatum, constrictistylum, impostor, mysticium, neomacropyga, and woodorum are new. Species of the last subgenus are segregated into three species groups. A lectotype is designated for P. ursinum (Edwards). Descriptions, distribution maps, keys, and 158 illustrations for the identification of the known adults, pupae, and larvae are provided.

The subfamily Midilinae Munroe, 1958b, is revised for the first time as a discrete and coherent group, though Hampson (1895) associated three genera and five species as part of his subfamily Schoenobiinae. Seven genera, 45 species, and six additional subspecies are recognized in the present study, of which the following one genus, 27 species, and five subspecies are described as new: Hositea punctigera, Brazil and Peru; H. regina, Brazil; H. cyanops, Surinam, Brazil and Bolivia; Cacographis osteolalis azteca, Mexico and Central America; C. o. inca, Peru; C. o. sara, Bolivia; C. macrops, Bolivia; Dismidila hermosa, Mexico; D. regularis, Colombia; D. similis, Bolivia; D. obscura, Brazil; D. pallida, French Guiana; D. gnoma, Guatemala; D. drepanoides, Peru; Midila lamia, Brazil and Guianas; M. larua, Venezuela; M. quadrifenestrata subfuscifusa, Guianas; M. thessala, Bolivia, Brazil; M. strix, Peru; M. daphne minor, Gorgona I., Colombia; M. agrippina, Bolivia, Peru; M. poppaea, Guianas, Colombia, Peru; M. crenulimargo, Peru; M. latipennis, Ecuador; M. discolor, Ecuador; M. sympatrica, Guatemala; M. fonteboalis, Brazil, Peru; M. centralis, Guatemala; M. soror, Panama; M. guianensis, Guianas; M. equatorialis, Ecuador; Pastranaia, type-species Hygrochroa fenestrata Ménétriés; P. tumidifrons, Brazil, Guianas, Colombia. Phryganomima Hampson is transferred to Midilinae from Pyralinae. Midila attacalis Walker is raised to a subspecies of M. quadrifenestrata (Herrich-Schäffer) and M. orfilai Pastrana is sunk as a synonym of M. g. attacalis. Tetraphana lilacina Pagenstecher is transferred from Midila to Pastranaia and Midila martinezi Pastrana and M. lilacina Whalley are sunk as synonyms of it.

The genus Ostrinia is revised and the species limits, phylogeny, host relationships, geographical distribution, and the economic implications of species limitation are briefly discussed. Twenty species and 24 additional subspecies are recognized, of which 5 species and 19 additional subspecies are described as new. One new name is proposed for a homonym and a number of changes of synonymy and status are made.

The noctuid subfamily Heliothidinae, which is represented in North America by 158 species, is redefined, largely on the basis of male genitalic characters. Of genera included in the subfamily in McDunnough's 1938 check list, only four are recognized as valid, these being Heliothis Ochs., Schinia Hbn., Heliolonche Grt., and Melaporphyria Grt. Helicoverpa Hdwk., which was described subsequent to the appearance of McDunnough's list, and Protoschinia which is described as new here, are also included. Grotella Harv., Hemigrotella B. & McD., and Neogrotella B. & B. are not considered heliothidine genera and are removed to the Stiriinae.Eight genera, which have been assigned to the Amphipyrinae because they lack the mid and hind tibial setae characteristic of other heliothidine components, have also been incorporated in the Heliothidinae; these genera are Microhelia Hamp., Heliothodes Hamp., Baptarma Sm., Eutricopis Morr., Derrima Wlk., Erythroecia Hamp., Rhodoecia Hamp., and Pyrrhia Hbn. Because of the close similarity in structure and habits between these genera and those previously mentioned, the two groups are considered to constitute a monophyletic assemblage within the Noctuidae, despite the discrepancy with respect to mid and hind tibial setae.A key to the 14 North American genera of the Heliothidinae is presented. Descriptions of genera and figures of the male and female genitalia of the type species of all valid genera and of many genera in synonymy are provided. Canthylidia Butl. and Timora Wlk. are newly synonymized to Heliothis, and Heliosea Grt. to Heliolonche Grt. A check list of the North American Heliothidinae is appended to the text.The possible phylogenetic relationship of the Heliothidinae to the Stiriinae is discussed. The latter group is raised from tribal rank in the Amphypyrinae to subfamily rank; a number of genera are added to it, and a provisional redefinition of the subfamily is presented.

The large and complex genus Euxoa is divided into six subgenera: Orosagrotis, Longivesica, Euxoa, Chorizagrotis, Pleonectopoda, and Crassivesica. Orosagrotis and Chorizagrotis have until now been considered as valid noctuid genera by many workers. Longivesica and Crassivesica are here described as new. The taxonomy and distribution of North American species in all subgenera except the very extensive subgenus Euxoa are considered in the present paper. Only 49 species in a probable North American Euxoa fauna of some 200 species are included in the five subgenera reviewed here, however.Within the genus, species have been segregated into subgenera and species groups largely on the basis of the structure of the male genitalia, and particularly on the conformation of the vesica of the male. Keys to subgenera, species groups, and species are presented. No new species are described. Subspecies are not formally considered because an adequate analysis of the often complex geographic variation is beyond the scope of this paper.