The toxicities of two commonly used soil insecticides, fonofos and phorate, were compared among one larval population of the corn wireworm, Melanotus communis (Gyllenhal), from sugarcane fields and three populations from potato fields in southern Florida. Fonofos toxicity did not differ among most populations; however, phorate toxicity did. Phorate was consistently less toxic to one population from potato fields. The toxicities of these two compounds to the population from sugarcane fields did not differ from those from potato fields, despite differences in insecticide pressure between the two crops.

Populations of larvae of the bertha armyworm, Mamestra configurata Wlk., in four physiographic regions of Manitoba showed similar trends over time: a decline from the outbreak of 1971–1972 to very low densities in 1975–1977, an increase to a peak during the years 1979–1981, and a subsequent decline. During the period of peak larval populations, brief (1 or 2 years) outbreaks [at least some fields with > 20 larvae per square metre) occurred at five locations in two regions, the Swan River Plain and the Valley River Plain, but not in the Western Uplands or the Manitoba Lowlands. In the first two regions, larval densities rose rapidly (from < 1.6 to > 13.8/m2) in 1 year. Although the general trend of population density was similar, there were differences in density among and within regions, and in the timing, severity, and duration of peak populations. Two parasitoids (Banchus flavescens Cress., Athrycia cinerea (Coq.)) and two pathogens (a nuclear polyhedrosis virus (NPV) and fungi of the Entomophthorales) occurred regularly in larval populations. Of these, B. flavescens had the highest constancy among collections and may help to keep bertha armyworm populations at low densities. NPV was rarely found among larvae from low-density populations but appeared in all populations that reached outbreak levels. No single biotic agent could be associated with the population declines because of multiple parasitism and the difficulty in partitioning mortality when only a single sample could be taken. The rapid increase of bertha armyworm larvae from very low to outbreak levels in 1 year will prevent predictions of outbreaks from being based on larval densities in the preceding year.

Examination of crop contents of three species of grasshoppers in outbreak densities on desert grassland of eastern Arizona revealed that all three were ingesting a mixed diet of plants. Crops of nymphal and adult Aulocara elliotti (Thomas) contained an average of 67 and 93% dry weight of grass, respectively, placing this species in both the mixed graminivorous and the graminivorous categories. The preferred host plant of A. elliotti was Bouteloua gracilis (H.B.K.) Lag. but it was not an essential item, as a large population developed in a site where this grass was virtually lacking but other perennial grasses were present. Crops of nymphs and adults of both Melanoplus sanguinipes (Fabricius) and M. cuneatus Scudder contained chiefly forbs (88–100% of dry weight). The principal host plants were Erodium cicutarium (L.) L’Hér., Lupinus brevicaulis Wats., Microsteris gracilis (Hook.) Greene, and Plantago purshii Roem. & Schult. Both species of Melanoplus fit into the forbivorous category and evidence indicated they were in competition with each other for food. All three grasshopper species showed preferences for particular plant species and as a consequence had significantly different frequencies of plant taxa in their crop contents from what were present in the field.

Five new species, Apometriocnemus beringensis, Cricotopus (Cricotopus) bifurcatus, Doithrix dillonae, Hydrobaenus piloculus, and Paratrissocladius lawrencensis, are described. The following new combinations are established: Bryophaenocladius astis (Roback 1951b); Compterosmittia nerius (Curran 1930); Parakiefferiella subaterrima (Malloch 1915); Paratrichocladius nitidus (Malloch 1915); Pseudosmittia nanseni (Kieffer 1926); and Zalutschia sivertseni (Aagard 1979). New genus name synonymies are Maricladius Sublette, 1970 with Parakiefferiella Thienemann, 1936; and Prosmittia Brundin, 1956 with Pseudosmittia Goetghebuer, 1932. New species name synonymies are Spaniotoma (Trichocladius) senex Johannsen, 1937 with Trichocladius nitidellus Malloch, 1915 (= Acricotopus nitidellus); Hydrobaenus traenis Roback, 1957b with Hydrobaenus astis Roback, 1957b (= Bryophaenocladius astis); Compterosmittia clavigera Saether, 1982 with Camptocladius nerius Curran, 1930 (= Compterosmittia nerius); Cricotopus flannagani Saether, 1971 with Cricotopus macraei Saether, 1971; Gymnometriocnemus marionensis Saether, 1969 with Metriocnemus subnudus Edwards, 1929 (= Gymnometriocnemus (Gymnometriocnemus) subnudus); Gymnometriocnemus (Raphidocladius) acigus Saether, 1983 with Metriocnemus brumalis Edwards, 1929 (= Gymnometriocnemus (Raphidocladius) brumalis); Limnophyes spatulosus Saether, 1975 with Limnophyes borealis Goetghebuer, 1933; Limnophyes cristatissimus Saether, 1975 with Camptocladius fumosus Johannsen, 1905 (= Limnophyes fumosus); Limnophyes hudsoni Saether, 1975 with Limnophyes immucronatus Saether, 1969; Hydrobaenus hudsoni Saether, 1977 with Chaetocladius (Parachaetocladius) abnobaeus Wülker, 1959 (= Parachaetocladius abnobaeus); Parakiefferiella torulata Saether, 1969 with Camptocladius subaterrimus Malloch, 1915 (= Parakiefferiella subaterrima); Trichocladius helis Roback, 1957b with Orthocladius nitidus Malloch, 1915 (= Paratrichocladius nitidus); Syncricotopus fontinalis Saether, 1969 with Chironomus rufiventris Meigen, 1830 (= Paratrichocladius rufiventris); Pseudorthocladius (Lordella) comans Saether and Sublette, 1983 with Pseudorthocladius (Lordella) wingoi Saether and Sublette, 1983; Smittia triappendiculata Goetghebuer, 1931 with Camptocladius forcipatus Goetghebuer, 1921 (= Pseudosmittia forcipatus); and Psilometriocnemus cristatus Saether, 1982 with Psilometriocnemus triannulatus Saether, 1969. Major new distribution records are given for 49 species including 8 Nearctic and 32 Canadian. A key to adult males of Nearctic Limnophyes is given.

The genus Cricotopus of the arctic zone of the Nearctic region, represented by 14 species in seven species groups, is reviewed. Descriptive notes on 11 species supplement those given by Hirvenoja (1973), with addition of descriptions of immature stages of C. lestralis (Edwards) and larva of C. tristis Hirvenoja. Two new species names, C. beringensis and C. trilobus, are proposed. New species names synonymies are Chironomus basalis Staeger and Chironomus holmgreni Kieffer with Chironomus tibialis (Meigen) (= C. tibialis). Several undetermined individuals are assigned to the fuscus group. Eleven species are Holarctic in distribution, of which C. bicinctus (Meigen) and C. sylvestris (Fabricius) are circumboreal. Seven species are restricted to the arctic zone, two are wide-ranging in both arctic and temperate zones, and four temperate species barely extend into the arctic zone. Keys to all known life-history stages and some ecological data, primarily of larvae, are given.