The tribe Xyloterini is widely distributed in the Holarctic realm. It is comprised of three rather small but well known genera. The largest of these, Trypodendron Stephens, consists of about a dozen species and occurs throughout the Holarctic realm; five of these species occur in North America. Dendrotrypum Schedl contains six species that are known only from eastern Asia. Xyloterinus Swaine contains one species from eastern North America.

Head transverse, as broad as thorax; eyes prominent, not hairy; occipital carina absent; antennae far apart near top of eyes; upper face (“frons”) very short, nearly horizontal; lower face flattened and broad (Figs. 3, 4); antennae 21- to 23-jointed.

Notaulices present, extending almost to centre of mesonotum but remote from one another; prepectal carina absent; mesopleural furrow long and horizontal.

Predacious mites of agricultural and horticultural importance are almost entirely of the family Phytoseiidae Berlese, 1913. These mites have received considerable attention both biologically and systematically in recent years, since the discovery that they feed on phytophagous mites of the family Tetranychidae that are of economic importance in many parts of the world.

Nesbitt (1951) revised the family in part, and present knowledge of the Phytoseiidae is largely based on his work. Garrnan (1948) devised a system of chaetotactic nomenclature that was used by both Nesbitt (loc. cit.) and Evans (1952) and is followed in this paper.

Rescue wheat has been grown in the prairie regions of Canada and the United States since 1946 as a control for the wheat stem sawfly, Cephus cinctus Nort. Although there is no evidence of the existence of a strain of sawflies to which Rescue is not resistant, the possibility of the development of such a strain is an important consideration. Callenbach (1952) found no differences in the percentages of Rescue sterns cut by the progenies of sawflies reared the previous year in Rescue and in susceptible varieties of wheat.

The present work was done to determine whether a strain that would survive readily in Rescue wheat could be segregated by rearing sawflies continuously in this variety.

Differences in resistance of varieties of peas to the pea aphid, Acyrthosiphon pisum (Harr.), have long ago been shown in the field and by controlled rearings under glass, Russell and Morrison (1924, p. 63) apparently being the First to observe differences. Early investigations at Wisconsin by Searb (1932) showed that pea varieties differ in the number of aphids born upon them. Maltais (1937) corraborated these early findings and reported (1950) the development of a pure-line strain of aphid-resistant pea. The influence of resistance in peas upoil aphid development, reproduction, and longevity as investigated by Harrington (1941) with individual plants under controlled conditions in the greenhouse. His results confirmed the inability of the insect to develop and reproduce as fast on a resistant plant as on a susceptible one. Tt has been postulated that the composition of the available food in the host plant plays possibly the most important role in determining the resistance to aphid attack (Evans, 1938; Painter, 1941). Maltais (1948), Auclair and Maltais (1950), and Maltais (1951) gave preliminary reports on the probable factors in varietal resistance in peas.

An outbreak of the European spruce sawfly, Diprion hercyniae (Htg.), was discovered in the Gaspé Peninsula in 1930. By 1938, heavy infestations had developed west of the Gaspé Peninsula in Quebec, throughout New Brunswick and northern Maine, and in parts of Vermont and New Hampshire. Moderate to light infestations occurred through all other parts of the spruce forests of this region and extended from Nova Scotia, to the north shore of the St. Lawrence River, and west to Ontario.

This paper describes a successful attempt to tag adult females of the European pine shoot, Rhyacionia buoliuna (Schiff.) with Co60, chosen as a tagging agent because it is a gamma emitter with a sufficiently long half-life (5.3 years). Emphasis is placed on the preparation and application of the tracer material, the absence of immediately harmful effects of radiation on the insects, and the ability of the insects to behave normally with the tags in place. This work was undertaken in order so develop techniques for following the movements of large numbers of these insects.

The pine tortoise scale, Toumeyella numismaticum (Pettit and McDaniel), was epidemic on jack pine in Marinette, Oconto and Florence counties in northern Wisconsin during 1953 and 1954. In the spring of 1954, 2900 acres of jack pine plantation in Marinette County were heavily infested. Four hundred seventy-four acres had been killed during 1953 by the scale. Some of the timber had been expected to reach marketable pulp log size within the next four to five years. The infested plantations showed the same symptoms as those which died in 1953 had shown during that year.