A resumé of the North American literature concerned with hymenopterous parasites of bark beetles is presented. Morphology, seasonal history, host-tree selection, hyperparasitism, importation and colonization and their influence upon control of the host are briefly discussed.

Parasites of a given host or hosts of a known parasite can easily be found in two different lists. Parasites are listed below in an alphabetical list of bark beetle species. Hosts, including some species other than bark beetles, are listed under a separate list of parasite families and genera. Host-parasite associations in each list are supported by a numerical reference to the literature cited.

A new species of Ips is described and illustrated. This species is allied to I. interrupta and I. hunteri and is found attacking freshly dead or dying limber pine, (Pinus flexilus).

The paper describes a new species and genus of fly, Archidipteron walkeri (Nymphomyiidae: Diptera), found in samples seined by screens from the Molus river, New Brunswick, after spraying of the watershed with DDT in oil.

The species is compared with Nymphomyia alba, Tokunaga, of Japan and the affinities of the family discussed. It was concluded that these insects are only distantly related to other Diptera and are probably best considered as belonging in the Archidiptera, a suborder of the Diptera, as proposed by Rohdendorf.

The ecological position of the insects is discussed but definite conclusions are not drawn pending more information on life cycle, particularly of the, as yet unknown, larval stages.

Observations on the occurrence of Camnula pellucida (Scudder) on native grasslands in Saskatchewan indicated that such areas did not support large populations of this species except on the margins where these were adjacent to cereal crops. This supports the view that large-scale infestations arise when both a food habitat (cereals) and an oviposition habitat (short grass) are readily available to the insects.

A new genus of Otopheidomeninae is described, keyed, and based on a new species, Nabiseius duplicisetus. Larvae, nymphs, and females of this mite were found on the abdominal dorsum of a nabid bug, where presumably they are ectoparasitic, as with related species.

Preliminary studies on the association of the Douglas-fir beetle with species of Diptera found in windthrown Douglas-firs were conducted in 1962 and 1963. These studies revealed that larvae of Medetera aldrichii Wheeler preyed upon larvae and pupae bur only rarely on teneral adults of the Douglas-fir beetle whereas larvae of Lonchaea furnissi McAlpine did not kill the bark beetle in any stage. Adults of M. aldrichii lived up to i weeks at 70° F. on granary mites, and L. furnissi adults survived for more than 3 weeks on honey and Metrecal. Seasonal and daily emergence patterns from naturally infested Douglas-firs are presented and the effects of temperature and light on emergence and flight are discussed.

Stained sections of female adult Platypus wilsoni Swaine showed that the punctures concentrated on the caudal half of the pronotum are fungus pits or mycangia. A fungus resembling Tuberculariella sp. was cultured from this area. Mycangia were not found in male adults.

Group VI of North American Ips contains I. perturbatus (Eichhoff), I. hunteri Swaine, I. utahensis Wood and I. woodi Thatcher. A key and descriptions of species are given. Members of this group have the third declivital spine capitate with the tip conical and acute. The front of the head is evenly convex except in females of I. utahensis which have the lower part of the frons faintly elevated. I. woodi breeds in pine while the other three species breed in spruce.

The life history of Chrysomela crotchi, a univoltine species commonly found on trembling aspen, was studied in northwestern Ontario from 1959 to 1962. The most striking feature of its life history was the longevity of adults, which were capable of overwintering two successive years. Overwintered adults became active and began feeding in late May, and oviposition occurred from early June to late July. The incubation period was approximately 10 days and the three larval instars required approximately one month for development to the adult stage.

Females laid more eggs during their second season and the highest number laid was 326. The number of eggs in an egg mass averaged 37.6, and the average interval between the deposition of egg masses was 4 days. Males and females mated more than once, but only one mating was necessary for a female to produce viable eggs throughout the season. Males were capable of fertilizing more than one female and remained potent for more than one season.

Parasitism was low, and only two species of larval parasites were reared. Several predator species were observed preying on the immature stages. Predation and overwintering mortality appeared to be the most important control factors.

Egg distribution on a ponderosa pine 14 feet tall of a species of sawfly in the Neodiprion fulviceps complex is presented. Females prefer to oviposit on current year’s foliage. There was no consistency in position of egg cluster on the needle, length of needle, age or size of branch, vertical position in the tree or number of eggs per cluster in needles of different age. Oviposition was highest on south, southeast and east vectors of the tree. Two needles per fascicle were used more often on one-year-old foliage than on current foliage.

That insect flight is influenced by air ions was shown when blowflies, Phoenicia sericata Meigen, were exposed to air ions at ion currents of about 3.4 × 10−11 amp. Positive ions resulted in longer, faster flights than did normal laboratory air, and there were steep increases and decreases in speed. Negative ions resulted in relatively fast, steady flight that usually lasted longer than in positively ionized or in laboratory air. After exposure to positive ions, exposure to alternating polarities resulted in a steady net increase in flight speed but exposure to alternating polarities after exposure to negative ions had no effect on flight.

Hippelates pusio Loew. pupae in Puerto Rico were parasitized internally by Ooencyrtus submetallicus Howard, egg parasite of the southern green stink bug, Nezara viridula var. smaragdula Fab. Another case of divergent host preference is noted for Eupteromalus hemipterus (Walker), and the importance of soil-breeding Diptera in the propagation of beneficial organisms is demonstrated.