Responsesof seven species of pine-infesting beetles to traps baited with either turpentine, ethanol, turpentine and ethanol released from separate dispensers,or a 1:1solution of turpentine and ethanol released from one dispenser were assessedin three fieldexperiments. The weevil species, Pachylobius picivorus (Germar), and the cerambycid pine sawyer, Monochamus carolinensis (Olivier), were attracted to turpentine and were unaffected by the addition of ethanol. The ambrosia beetle, Xyleborus affinis Eichhoff, responded to ethanol alone but was not attracted to turpentine, nor did the presence of turpentine significantly affect its response to ethanol. The remaining four species displayed responses to turpentine that were enhanced by the addition of ethanol, but in different ways according to the method of deployment. Hylobius pales (Herbst) weevils and M. titillator (F.) sawyers displayed greatest attraction to turpentine and ethanol whether they were released from side-by-side dispensers or as a solution from one dispenser. The black turpentine beetle, Dendroctonus terebrans (Olivier), displayed the highest response to turpentine and ethanol in solution. The ambrosia beetle, X. pubescens Zimmermann, responded in low numbers to turpentine or ethanol deployed singly, but displayed an enhanced response (20-fold increase) to turpentine and ethanol deployed side-by-sideand an even greater response (60-fold increase) to a solution of turpentine and ethanol. Reasons for increased responses by some species to a solution of turpentine and ethanol over the two released separately are not clear; they may lie in different dosagesor evaporation rates of volatilesin the field. Laboratory analyses of trapped headspace volatiles from dispensers containing only turpentine and those containing a solution of turpentine and ethanol revealed no differences in the amounts of four principal monoterpene hydrocarbons (a-pinene, camphene, }3-pinene,and limonene) released over time. The synergistic effect of turpentine and ethanol for some speciesand not others may point to ecological differences between species with regard to the condition of preferred host material.

The process of resource utilization by Dendroctonus frontalis Zimmerman attacking loblolly pine, Pinus taeda L., was investigated. The quantitative relationship of attacking parent adult D. frontalis as a function of the normalized infested bole height is described by the model y = Ax(1−x)eBx. Greatest attack density occurs at the mid-bole of the tree and tapers toward the top and bottom. Gallery length (and hence eggs)/100 cm2 was independent of attack density. The relationship between gallery length (or eggs) per parent adult and parent adult density is described by the exponential decay curve y = AeBx, indicating that gallery length and egg population density are controlled by a density dependent compensatory feedback process operating instantaneously. Further support for the mechanism was obtained by analyzing the gallery length per parent adult at different locations on the infested bole. The relationship is described by the model y = [AeBx]/[x(1−x)] and indicates that gallery construction and egg population per attacking beetle increase in the upper and basal portion of the bole. The result is a uniform amount of food and space per individual of the developing population.

The bark weevilPissodes nemorensis, a pest of pines and exotic cedars in the southeastern United States, utilizes a male-produced aggregation pheromone. The presumed pheromone components, grandisol (cis-2-isopropenyl-1-methylcyclobutaneethanol) and its corresponding aldehyde, grandisal, were isolated from extracts of male volatiles and male hindguts. A field test in northern Florida showed that the combination of grandisol, grandisal, and slash pine (Pinus elliottii) bolts acted synergistically to attract large numbers of male and femaleP. nemorensis. These components deployed in various paired combinations were not as attractive as the tripartite mixture. There was no evidence that flying weevils were attracted to unbaited pine bolts. The aggregation pheromone forP. nemorensis appears to be similar to that of a parapatric sibling species,P. approximatus.

The within-sample distributions of gallery length (GL) and egg (E) density as well as their functional relationships to the infested bole were studied in an epidemic population of the southern pine beetle in southeast Texas.A least-squares linear regression analysis through the origin showed an average of 1.59 eggs per centimeter of gallery. GL accounted for 81% of the variation in E and thus is useful for estimating egg numbers. The density of attacking adults is unsatisfactory for predicting E.GL and E are uniformly distributed within but not among the 100-cm2 sample disks at a given height. The functional relationship of both variables to the infested bole is adequately described by the model y = (A+Bx)exp(Cln(x−x2)), where y = GL or E per 100 cm2, x = the normalized height on the infested bole, and A, B, and C are parameters to be estimated for each set of data.

Can. Ent. 110: 471-473 (1978) Xenoborus Reuter is synonymized with Tropidosteptes Uhler. Tropidostepres brooksi n. sp. is described from Saskatchewan, Manitoba, Ontario, and Quebec. The species was collected on Fraxinus spp. Reuter (1908) described Neoborus commissuralis and proposed the subgenus Xenoborus for it. Soon after (1909) he transferred commissuralis to Tropidosteptes Uhler (1 878) and described petitti and plagifer under that genus. Van Duzee (1 9 16a, b ) raised Xenoborus to generic status and transferred commissuralis and plagifer to it respectively. Knight (1917) transferred petitti to Xenoborus and described X. neglectus. Later (1927Later ( , 1929 he added chinaonthi and selectus to it. Xenoborus has retained generic status to the present day.Slater (1950) studied genital structures of Neoborus Distant (1884), Tropidosteptes, and Xenoborus and suggested that the three genera were congeneric. Carvalho (1954) synonymized Neoborus with Tropidosteptes. Kelton (1959) studied the male genital structures of Tropidosteptes, Xenoborus, and Neoborella Knight (1925) and also suggested that the three genera were congeneric. Further studies of the species included in those genera show that Tropidosteptes and Xenoborus are congeneric but Neoborella may be retained as a distinct genus.In addition to the similar structures of the male and female genitalia, species of Tropidosteptes and Xenoborus are also similar in shape and appearance, and all have similar type of habitat. The species are rather large, generally over 5.0 mm in length, elongate and subparallel. The frons are smooth or punctate but not transversely grooved or striate. All are confined to deciduous trees and mostly to Fraxinus spp. The character of the carinate lateral margins of the pronotum used to separate them into two genera is weak and inconsistent. Species in both genera have carinate, partly carinate, or rounded pronotal margins.Although the male genital structures and puncturation on the pronotum in species of Neoborella show a close relationship to those of Tropidosteptes and Xenoborus, species of Neoborella are easily separated from the others by the distinctly grooved and striate frons. They also differ in size and shape. Species of Neoborella are rather small, less than 5.0 mm in length, and oval or oblong in shape. So far as is known species of Neoborella are confined to dwarf mistletoe growing on conifers.Herewith Xenoborus Reuter is synonymized with Tropidosteptes Uhler, and Neoborella Knight is retained as a distinct genus. A new species belonging to Tropidosteptes is described, and illustrated.