Characteristics of the cocoons, cephalic structures, spiracles, and skins of 97 species and 19 genera of the tribe Campoplegini (Hymenoptera: Ichneumonidae: Campopleginae) are described and illustrated and keys are given for identification of the genera and species. An additional five species and two genera that were described and illustrated in earlier papers (Finlayson 1967, 1969) are included in the keys, for a total of 102 species and 21 genera. Characteristics of final-instar larvae were found that support most of the generic entities defined on the basis of adult characteristics, and new relationships were revealed that may assist with taxonomic problems in the group.

The genus "Paraphlepsius" of authors is divided into two genera, Paraphlepsius Baker and Pendarus Ball which also encompass the nearctic species of "Phlepsius" of authors.Pendarus is divided into two subgenera: Pendarus sensu stricto with nine species, and Remadosus Ball with five species. P. likrois n. sp., P. crucifix n. sp., and the female of P. cirrus (DeLong) are described.Paraphlepsius is divided into five subgenera: Strephonius n. subgen. with nine species, Sabix n. subgen. with five species, Gamarex n. subgen. with 32 species, Paraphlepsius sensu stricto with 11 species, and Paraphysius n. subgen. containing 11 species. Nine new species and one new subspecies are described: P. delongi, P. exilis, P. geneticus, P. lupalus, P. luxuria, P. quadratus, P. superior, P. umbellatus, P. zanclois, and P. brunneus ravus. The male of P. maculosus (Osborn) and the females of P. cinereus (Van D.), P. divergens (Oman), and P. supinus (DeLong) are described.The following new synonymies are made: lippulus Ball = auroalbus Walker; slossonae Ball and tullahomi DeLong = stipatus Walker; fastuosus Ball = punctiscriptus Van Duzee; fulviceps Osborn & Lathrop = uhleri Van Duzee; dampfi DeLong = obvius Oman; optatus Crumb = strobi Fitch; bipartitus DeLong = carolinus Lathrop. The following species are removed from synonymy: franconianus Ball, micronotatus Osborn & Lathrop, nebulosus Van Duzee, and uhleri Van Duzee.All available types were examined, and lectotypes are designated for bifidus Sanders & DeLong, electus DeLong, hemicolor Sanders & DeLong, lobatus Osborn, palustris Sanders & DeLong, particolor Sanders & DeLong, planus Sanders & DeLong, stipatus Walker, strobi Fitch, tennessus DeLong, and umbrosus Sanders & DeLong. Neotypes are designated for apertinus Osborn & Lathrop, carolinus Lathrop, and torridus Lathrop.Previously undescribed characters of the female internal genitalia are described and illustrated. All species are described, keyed, and illustrated for both sexes where these are known.

The genus Lygus Hahn is revised for North America. The new synonyms (to the left of the equal sign) are: ceanothi var. deliticus Knight = humeralis Knight; convexicollis var. coloratus Knight and dolichorhynchus Stanger = convexicollis Reuter; nigritus Knight = ravus Stanger; brindleyi and fultoni Knight = robustus (Uhler); superiorensis Knight = columbiensis Knight; frisoni Knight = rubroclarus Knight; nigrosignatus Knight = elisus Van Duzee; ultranubilus Knight and epelys Hussey = nubilus Van Duzee; and nubilosus Knight and usingeri Stanger = nubilatus Knight. The 34 species known to occur in North America are: abroniae Van Duzee, aeratus Knight, atriflavus Knight, atritibialis Knight, borealis (Kelton), bradleyi Knight, ceanothi Knight, columbiensis Knight, convexicollis Reuter, desertinus Knight, elisus Van Duzee, hesperus Knight, humeralis Knight, lineolaris (Palisot de Beauvois), mexicanus Kelton, nigropallidus Knight, nubilatus Knight, nubilus Van Duzee, oregonae Knight, perplexus Stanger, plagiatus (Uhler), potentillae Kelton, ravus Stanger, robustus (Uhler), rolfsi Knight, rubroclarus Knight, rubrosignatus Knight, rufidorsus (Kelton), shulli Knight, solidaginis (Kelton), striatus Knight, unctuosus (Kelton), vanduzeei Knight, and varius Knight.Species are redescribed, seasonal variations in size and colour are discussed, and distribution maps and host plants are included. The adult males are illustrated and a key for their identification is given.