In the prairie region of Western Canada certain species of bumble bees are the principal pollinators of red clover, Trifolium pratense L. (Hobbs, 1957). Certain bumble and leaf-cutter bees are the only effective pollinators of alfalfa, Medicago sativa L., in Western Canada (Hobbs and Lilly, 1954; Hobbs, 1956; Peck and Bolton, 1946; Stephen, 1955). Unfortunately, bumble and leaf-cutter bees are seldom very abundant.

The genus Roederioides was erected by Coquillett in 1901 for the single species juncta Coquillett, described from Saranac Inn, New York. The species has since been recorded only from Mt. Washington, New Hampshire. A second species has been described from the Madeiras by Frey. This paper describes five new species from North America and presents a revised description of the genus.

The type of the genus, juncta, was collected in association with black flies, and recent collections have been made from black fly swarms. It is possible that juncta, and possibly other species of the genus, are predators of black flies, both as adults and as larvae.

In a survey of wood-feeding Anobiidae occurring in the Northeastern United States and adjacent Canada, a species of Ptilinus was found which the author believed to be new and for which the trivial name friendi was proposed (Simeone, 1960). However, having had the opportunity during the summer of 1960 to examine and collect European species at the Forest Products Research Laboratory, Princes Risborough, England and at der Forstliche Bundes-versuchsanstalt Mariabrunn in Schönbrunn, Vienna, Austria, the author now believes his specimens to have been introductions of the common species, Ptilinus pectinicornis L. In view of rhe economic importance of this species in other parts of the world, it seems advisable to describe in some detail the adult male and female as well as to compare some of the characteristics whereby the insect can be distinguished from closely allied species.

Some information of interest on the postdiapause development of the larch sawfly, Pristiphora erichsonii (Htg.), and its tachinid parasite Bessa harveyi (Tnsd.) has been obtained in the course of laboratory rearings. Sawfly cocoons were placed in cold storage at 2 to 3°C. in September or October and held until the following year, usually late March, when they were incubated at 10 or 15°C. They were then held at constant temperatures until emergence was complete. Sawfly and parasite emergence was recorded daily.

During a study of the parasites attacking the forest tent caterpillar, Malacosoma disstria Hbn., a ready means of identifying puparia of the common dipterous parasites proved necessary so that those individuals that failed to develop beyond the puparial stage in laboratory rearings might be identified in advance of lengthy cold treatment and incubation. The following key was therefore developed on the basis of the study of series of puparia associated with adults determined by the Entomology Research Institute. The key includes the ten most common dipterous parasites of the tent caterpillar in Ontario, seven of which have been included in a similar key to the parasites of Malacosoma spp. in British Columbia (Ross 1953). The terminology used in these two keys is similar, and is adapted from Green (1921).

The two-spotted spider mite, Tetranychus telarius (L.), is a well known pest of many plants in greenhouses. It is notoriously difficult to conarol, especially when resistant populations develop, and usually requires frequent acaricidal treatment during the growing season. Biological control has sometimes been suggested in view of the success that was achieved by this method against other greenhouse pests and because the environment is controllable to some extent, but only a few attempts have been made.

The Neodiprion sawfly studied in this investigation is an undetermined species which attacks sugar pine, Pinus lambertiana Dougl., in California. The conditions of the infested area were particularly suitable for an investigation of some of the basic factors affecting distribution of cocoons on the ground. The efforts of previous workers (Prebble, 1943; Ives and Turnock, 1959) were complicated by dense stand conditions and deep, variable pound cover. The sawfly discussed here was found in considerable numbers on an isolated, young sugar pine at Grass Valley, California. The tree was 19 feet high, 16 vears old, with s diameter of 5.5 inches. The infestation was presumed to be recent as no effect on diameter growth was found, even though the tree possessed only the current year's foliage. The ground cover was extremely sparse and the soil was a compacted, sandy-clay, typical of many foothill areas in California.

Recent study of the male genitalia in the Miridae (Kelton, 1959) showed that the Palearctic Stenodema virens (L.) does not occur in North America. The six other species that have been reported in the North American literature are: dorsolis (Say), vicinum (Prov.), trispinosum Reut., sequoiae Bliven, falki Bliven, and imperii Bliven. The three species described by Bliven (1955, 1958) were not available to me for study, however, Bliven (1960) has recently published a paper containing figures of the male genital claspers of these species. These appear to differ considerably from those of virens, vicinum and trispinosum as well as amongst themselves.

The satin moth, occurring widely throughout Europe and Asia as a defoliator of poplars and willows, was first found in North America near Boston, Mass., in 1920. It was first noted in the Maritime Provinces in 1930 (Reeks and Smith, 1956). During 1920 it was found in New Westminster, British Columbia, and in 1921 a larger infestation probably of several years' standing was discovered in Vancouver, which Glendenning (1932) believes to be the original point of introduction into British Columbia. In 1922 the insect was discovered at Bellingham, Washington, and it has since spread throughout western Washington and Oregon.

The flight capacity (duration and velocity) is an important phase of the flight behaviour of economically significant insects such as the Douglas-fir beetle, because it influences the feasibility of control or preventive measures which might be considered. An understanding of the flight capacity and how it varies in relation to environmental factors is necessary to evaluate the beetles' power of dispersal under different seasonal conditions. This would help to detect new areas of infestation by directing or narrowing the search. It also would help evaluation of the hazard at hand in timber surrounding the infestation and be a further aid in determining the size of areas of sanitation required around the comparatively beetle-free areas needed for special purposes, such as parks.

Two of the most important factors that contribute to the success of a parasite population are (1) the ability to find hosts and (2) the ability to oviposit in hosts when found. The theories of Thompson (1922, 1924), Nicholson (1933) and Nicholson and Bailey (1935), which have commanded attention in the field of population dynamics for a number of years, emphasized the importance of these factors in quite different ways.

Thompson assumed that the parasites have no difficulty in finding their hosts but have a constant egg supply whereas Nicholson assumed that the egg supply is virtually unlimited but that the parasites have a fixed and limited searching ability which he called their ‘area of discovery’.

The discovery that most plant-bugs emit, when disturbed, a kind of highly penetrant and nauseous odour is not of recent origin. However, it has since then been thought that the presence of such odoriferous scents exists probably in direct adaptation to the needs and habits of their possessors. The frequent occurrence of such an odour consequently stirred the curiosity of the earlier workers to determine the exact source of this scent. No documentary account of such an attempt was, however, available until 1833 when Leon Dufour published an account of the anatomy and physiology of Hemiptera. It was thus revealed by him that the real source of the odour was actually a gland, on each side, in the ventral part of the metathorax, opening to the exterior by means of very small apertures, lying one on each side of the metasternum between the second and third pairs of legs. He worked on many hemipterous bugs, and in Cimex lectularius mentions, for the first time, in addition to the glands, a median reservoir which may be oval or round and membranous in appearance. Dufour's publication gave further impetus to the following workers, and thereafter we find persistent attempts having heen made from time to time to work out the morphology of the glands. It may be mentioned that in view of the later discoveries of the chemical nature and the odour of the secretion in various insects, the use of the term Scent-apparatus would be more precise than stink or repugnatorial scent-apparatus, employed by most of the workers up to this day, for the secretion is not repugnant in many insects; in some it has even an agreeable odour like that of ripe bananas or ether. Brindley (1930) also seems to prefer the use of the term Scent-apparatus.

Börnerina Bramstedt is a genus of aphids that breeds only on species of Alnus L. Inclusive of the new species described herein the genus is composed of two species, of which B. depressa Bramstedt is the European representative.

Betulaphis Glendenning is a larger genus than Börnerina and as the name implies is restricted to species of Betula L. Although the genus was described in North America there have been no North American records subsequent to the original description (Glendenning, 1926). Elsewhere, the genus is known to occur in Europe, Iceland, Greenland and New Zealand. In this paper three species are recorded for North America, two of which are described as new.

In July, 1959 I reared a polyembryonic encyrtid from a species of Lithocolletis attacking Alnus crispa (Ait.) Pursh in the lake region around Ohio, Nova Scotia. It represents a species and genus new to science.

Gibberella, new genus

Type species: Gibberella scutellata Miller, new species.