Biological control attempts against the weed Hypericum perforatum L. in the interior of British Columbia are summarized. Three of the insects introduced, Zeuxidiplosis giardi Kieff., Agrilus hyperici (Cr.), and Chrysolina varians (Schall.), did not survive, and reasons for their failure are discussed. Two beetles, C. hyperici (Forst.) and C. quadrigemina (Suff.), are established and their population build-up in several areas is followed over a period of 15 years. The beetles reach their optimum effectiveness in different moisture zones but neither species is effective at the arid end of the H. perforatum range. A moth, Anaitis plagiata L., was released in this zone in 1967.

A new genus Scalponotatus is described, with nine new species from North America: maturus from Arizona and California, and albicornis, albipes, capitatus, chillcotti, howdeni, insignis, mexicanus, and mimosus from Durango, Mexico. Strongylocoris albibasis Knight is placed in this genus (n. comb.). A key is provided and male genitalia of all the species are illustrated.

Virgin females of Melanoplus sanguinipes (Fabricius) crowded in cages laid normal egg pods whereas solitary ones did not. An average of 8.3 pods per female were laid at a rate of 0.12 pod per female-day. This is less than those laid by fertilized females, and the difference seems to be in the rate of mobilization of materials for the eggs; 56.5% of the eggs showed no development. The remainder developed to varying stages and 5.6% hatched. Diploid, haploid, and subdiploid chromosome numbers were found in parthenogenetic embryonic tissue.

Newly hatched Oryzaephilus surinamensis (L.) were reared on a chemically-defined diet at 32 ± 2 °C and 75 ± 5% relative humidity. Addition of serine to the diet containing glycine was not beneficial to the insect and became harmful at a concentration greater than 10.0 mg/g. Serine was able to replace glycine almost completely in the glycine-free diet for this insect. The results suggest that glycine, but not alanine or threonine, is the precursor for serine biosynthesis in O. surinamensis. They also suggest that serine and glycine are not completely interconvertible by this organism.

The morphology and fine structure of the maxillary and mandibular stylets of the green peach aphid, Myzus persicae (Sulzer), are described from sections, whole mounts, and two-stage replicas. The mechanisms of penetration of the host plant are discussed.

The last three larval instars of each of the 25 species of mosquitoes reported from New England have, with very few exceptions, been studied. Characters useful in separating the larval instars of Aedes are discussed, and a key to differentiate the four larval instars, regardless of species, is presented. By making use of characters constant in all instars of a species, and by noting variations between and within instars, a key is presented which should permit the identification of most New England Aedes material, mounted or unmounted, in any of the final three larval instars.

Tuberculatus cornutus is described from Turkey, its affinities noted, and a combined key to the world species of Tuberculatus Mordwilko and Tuberculoides v. d. Goot is given. Revisionary notes on Tuberculoides are offered and Tuberculoides eggleri (Börner) is transferred to Tuberculatus.

Maintenance of predacious arthropods in apple orchards requires both the judicious use of chemical sprays and the presence of adequate food supplies. When the common food source, the European red mite, Panonychus ulmi (Koch), is depleted by either a selective chemical, such as Animert V-101, or by excessive activity of the predators, the apple rust mite, Vasates schlechtendali (Nal.), if present, provides an alternate food. This enables survival of sufficient numbers of predators to prevent resurgence of the red mite within the same season.

Physical activity in Blaberus giganteus (L.) loosely follows a recurrent temporal pattern corresponding to the light–dark cycle. Differential haemocyte counts were made from serial blood samples taken before and after dark from individual adults in a brief attempt to determine whether the haemocyte population changed regularly also with this cycle. In 4 of the 16 individuals tested there was a substantial increase in the relative number of spherule cells and a somewhat proportional decrease in granular haemocytes after dark. In this species, these two haemocyte categories differ mainly in the size and composition of their cytoplasmic inclusions. The proportional change in their numbers is therefore considered to be the result of chemistry rather than a shift in populations of entirely separate kinds of cells. Retention of the two categories may be useful for indicating physiological changes in the blood. It seems possible that the cyclic change in numbers indicated here for these categories is more usual than shown, but is not revealed by the method employed. It seems sufficiently large however to warrant consideration in the design and interpretation of experiments relating to haemocyte populations.

The serological relationships of Pissodes strobi (Peck) and P. approximatus Hopkins were examined using turbidimetric and immunodiffusion analyses. Hylobius pales Hbst. was used for heterologous comparisons. When turbidimetric analyses were performed using anti-strobi sera, heterologous reactions with P. approximatus were stronger than homologous reactions. Moreover, immunodiffusion tests substantiated this. These results appear to have broken a cardinal rule of serology: that hererologous reactions do not exceed homologous reactions in magnitude.These results could he due to a simple quantitative variation in the antigen extracts or to possible cross-reactivity between antigenically similar proteins. Another possibility is that the two populations are not separate species. Evidence obtained in this study seems to be in accord with cytological evidence obtained hi previous studies and does not support the designation of P. approximatus as a valid species.

Feeding tests with adult Exeristes comstockii (Cresson) showed that each of the 10 amino acids commonly recognized to be "essential" is required for egg production. Fecundity on a diet where only these 10 constituted the amino acid component equalled that on the control diet which contained 19 amino acids. Fecundity was reduced by 80% on diets in which Na+ was substituted for K+ and by one-third when K was the only mineral added. Omission of Mn2+ or Ca2+ from, or addition of Zn2+ to, the control salt mixture (Wesson’s) did not affect fecundity. Females fed the control (chemically defined) diet or its 10% dilution (sucrose content maintained) for 30 days in the absence of host larvae laid more eggs initially when hosts were supplied than did females fed 1% control diet, honeydew, or 10% sucrose for a similar period. Thus, for E. comstockii, only food with a relatively high quantity and quality of amino nitrogen fed during absence of host larvae will significantly increase initial fecundity when such hosts are later encountered. This knowledge affects treatment of parasites when being held before release in biological control programmes.

The range of the face fly, Musca autumnalis De Geer, has extended from the site of its first North American occurrence in Nova Scotia in 1952 to the northern half of the United States from coast to coast and every province in Canada. The first recorded appearance in Western Canada was at Virden, Man., in 1964 and it has since become established in eastern Saskatchewan. Face flies moved from Washington and Idaho into British Columbia in 1966. In 1967 they spread to most areas of the southern half of British Columbia and into southwestern Alberta through the Crowsnest Pass. Moisture and shade in pastures influenced the numbers of face flies seen on cattle and resulted in higher numbers than under dry prairie conditions.

A method is described for mass-rearing Chrysocharis laricinellae (Ratzeburg) on larch casebearer larvae, employing a water culture system for tamarack. The rearing unit accommodates a well-defined episode (limited contact) in the interaction with its host. The yield is about 100 healthy parasites obtained from 300 cases, when the initial inoculum was 15 parasite females.

Drepanaphis pallida is described from specimens collected on Acer saccharum Marsh. in Ontario. In structure and colour it is very similar to Drepanaphis granovskyi Smith and Knowlton, from which it can be distinguished by the relative sizes of the dorsal abdominal tubercles and the length of the cornicle.

The summer forms of two aphids, Rhopalosiphum padi (L.) and R. fitchii (Sand.) are similar morphologically, but R. padi has a chromosome count of 2n = 8, and R. fitchii of 2n = 10. Observations were made on these species on wheat, oats, and barley in the field and laboratory, using chromosome counts to verify species identity. Although they inhabit overlapping niches on the same host plants, there are small differences in behavior. Both species were found on barley in the field, although R. padi is much more abundant than R. fitchii. Both species were successfully reared on Poa pratensis L. and P. trivialis L. in a growth room. R. padi could be reared on shepherd’s-purse, Capsella bursa-pastoris (L.) Medic, but not R. fitchii.