The spatial and statistical distribution of eggs and larvae of the wheat midge, Sitodiplosis mosellana (Géhin), in wheat in northeastern Saskatchewan were investigated. The highest number of each stage occurred in the top third of the head and the lowest in the bottom third. Because of this the entire wheat head is considered an adequate sample unit for density estimates of the two life stages. Sample sizes required to estimate egg and larval populations with given levels of precision were determined. A sequential sampling plan for larval populations was derived using Green’s and Iwao’s methods. Both methods gave similar results; however, the number of samples required to reach a decision was higher using Green’s method than using Iwao’s.

The genus Parabarrovia Gibson, with one included species, P. keelei Gibson, was previously known from the original type material collected in the MacKenzie Mountains, Northwest Territories, in northern Canada. The known range of P. keelei is extended to include other areas in Beringia, namely, Yukon (British Mountains), Alaska (Brooks Range and Seward Peninsula), and the USSR (Wrangel Island). The immature stages are described for the first time. A second species of Parabarrovia, P. ogilviensis Lafontaine, also known only from the Beringian area, is described from the Ogilvie Mountains, Yukon, Canada. The position of Parabarrovia within the Noctuidae is reviewed and the genus is tentatively retained within the subfamily Noctuinae. Adults, including genital characters, and the immature stages are described and illustrated for both species.

The following new taxa of Xantholininae are described: Lithocharodes scutifer sp. nov. (Arizona), Habrolinus californicus sp. nov. (California), H. hardyi sp. nov. (California and Oregon), H. abdominalis sp. nov. (California), H. andrewsi sp. nov. (California and Oregon), Linohesperus spiculifer sp. nov. (California), L. iaculator sp. nov. (California), L. montivagus sp. nov. (California), L. priapus sp. nov. (California), Neohypnus coloratus sp. nov. (Florida), Oxybleptes meridionalis sp. nov. (Florida).

The genus Timagenes Smetana 1982 is placed as a subgenus of the genus Habrolinus Casey 1906 (new status). The treatments of the genera Habrolinus and Timagenes in my revision (Smetana 1982: 134–143) are entirely rewritten. A new key to the known species of Linohesperus Smetana 1982 is given.

Additional data on taxonomy, bionomics, and geographical distribution of many species of Xantholininae in North America are presented.

We examined the within-crown distributions of male and female bagworm, Thyridopteryx ephemeraeformis (Haworth), pupae on Juniperus virginiana L. as a function of prior defoliation. This was to evaluate the hypothesis that the differential movement of females to the upper crown before pupation would be strongest on heavily defoliated trees. Differential stratification of the sexes occurred irrespective of degree of defoliation, and despite the fact that competition, as evidenced by higher mortality of pupae and reduced weight of egg masses, was apparently greatest at the top of moderately and severely defoliated hosts. There was no relationship between height of pupation and risk of parasitism for either sex. Female larvae were ca. 4-fold more likely than males to abandon a low-lying host upon which they had fed and to ascend the trunks of nearby trees before pupating. Enhancement of larval dispersal by females is the most plausible explanation for the stratified distribution of bagworm pupae within trees.

The Tipulidae occurring in madicolous habitats of eastern North America are briefly discussed. Biological information is given for Dactylolabis montana (Osten Sacken) and D. hudsonica Alexander. A larval key to separate them is provided, as well as descriptions of larvae and pupae for both species.

The efficacy of mixtures of permethrin and Bacillus thuringiensis var. kurstaki Berliner (B.t.), Autographa californica (Speyer) nuclear polyhedrosis virus (ACNPV), or Pieris (= Artogeia) rapae (L.) granulosis virus (PRGV) against the cabbage looper, Trichoplusia ni (Hübner), and the imported cabbageworm, P. rapae, was assessed by field plot tests. Protection of the crop and yield by plots treated with several of the reduced-dosage mixtures were similar to protection and yield by plots treated with permethrin at the full rate, demonstrating a feasible procedure for reducing the amount of chemical insecticide applied without sacrificing protection of the crop. Furthermore, efficacy of the biological component of the mixtures, B.t. or viruses, was frequently enhanced by low concentrations of the chemical component on the mixture.

Two new species of aphids are described from Pennsylvania, Uroleucon (Lambersius) stoetzelae sp. nov. from Achillea millefolium L., and Uroleucon (Uroleucon) floricola sp. nov. from Aster sp.

Different insecticide spray regimes were tested in 1984, 1985, and 1986 to determine the optimal time to control the Colorado potato beetle, Leptinotarsa decemlineata (Say), on Russet Burbank potatoes in New Brunswick. Insecticides applied in mid-July at the peak of larval abundance when plants were entering into bloom had the greatest efficacy in controlling beetles and protecting the yield. A single insecticide application at 50% bloom was 12–17% and 82–95% more effective than one application at bloom and full growth, respectively.

Liriomyza sonchi Hendel was screened for its host specificity as a potential biological control agent against sow-thistles (Sonchus spp.). Recent literature indicated that L. sonchi is recorded frequently from Sonchus spp., but also from Arnoseris minima Schweigger and Koerte and Reichardia arabicum Hochstetter and Steudel. A total of 78 plant species were tested, including 37 species in the Cichorieae (Compositae). In no-choice tests, feeding punctures were observed on species in the closely related genera Aetheorrhiza, Crepis, Lactuca, and Taraxacum, and such distantly related species as Helichrysum bracteatum Andrews var. monstrosum Hortorum (Inuleae tribe, Compositae) and Pisum sativum L. (Leguminosae). From 0.04 to 0.67 adults per female were produced on Aetheorrhiza bulbosa (L.), Crepis dioscordis L., C. rubra L., Leontodon hispidus L., and Taraxacum officinale Weber as compared with about 23 per female on its host, Sonchus arvensis L. No species in these genera other than Sonchus are reported as hosts in the field in Europe and they are therefore considered to be cage-induced hosts. Because of its economic importance, 10 cultivars of lettuce, Lactuca sativa L., were exposed to a total of 837 females in no-choice tests. One puparium and one adult (0.006 per female) were produced. In one replicated choice test with 150 females, no mines were produced on lettuce. It is concluded that the field host range of L. sonchi is restricted to Sonchus spp.