Vitamin K1 added to a basic diet for the house cricket, Acheta domesticus (L.), significantly improves growth of male and female larvae. Growth is significantly better with 18.7 μg K1/g than it is with an equimolar amount of vitamin E. Unlike vitamin E, however, vitamin K1 is without effect on reproduction. Vitamins K3 and K5, and coumarin, have no effect or a slightly inhibiting effect on growth, and no effect on reproduction.

Dorcatomophaga (Nearctomophaga) jonesi n. subgen., n. sp. is described. Subgeneric characters are compared between the Nearctic and Palearctic forms. Representatives of the genus have not previously been recorded from North America.

Aerial photographs of corn fields in southwestern Ontario were photographically enhanced and subsequently computer-analyzed to determine levels of corn aphid infestation. The flight line included 87 fields, 42 of which were infested to varying degrees. The levels of infestation varied from 35.6% to 67.1% determined from five representative fields.

A natural virus epizootic, caused by a nuclear polyhedrosis virus, was observed in several populations of the European skipper, Thymelicus lineola (Ochs .), at Normandin, Que., in 1974 (Smirnoff 1974). A substantial supply of this virus was collected and experiments were conducted under laboratory and field conditions to evaluate its pathogenicity against the skipper, its possible transmission from one generation to the next, and its potential as a means of control of T. lineola, a serious insect pest of forage crops in several regions of Quebec (McNeil et al. 1975).

Pupae of the yellow fever mosquito, Aedes aegyti (L.), were examined for glycogen and lipid content under normal conditions and following exposure, as fourth-instar larvae, to 0.1 ppm of the insect growth regulator, Altosid® (isopropyl 11-methoxy-3,7,11-trimethyl-dodeca-2,4-dienoate).

The glycogen reserves of control and experimental insects show similar rates of utilization up to about 24 h of pupal life, but at 48 h, the glycogen reserves of treated animals are depleted. Examination of pupal lipid content indicates that insects treated with Altosid begin pupal life with lipid reserves which are considerably less than those of control animals.

The reduced energy reserves available to newly emerged adults may contribute to premature mortality.

A new species of sarcophagid, Colcondamyia auditrix, is described, which locates its cicada host by sound. The fly was shown to respond to the mating song of the male cicada, and the majority of parasitized cicadas were male. Parasitism of females occasionally occurs when they are attracted to males simultaneously with the parasite. Levels of parasitism varied from 18.6% in 1962 to 0.2% in 1967 to 14.1% in 1973. Male cicadas lost their sound producing capability following parasitization, rendering them inaccessible to further female flies and thus apparently preventing multiple parasitism.

Three new species of the genus Xylocoris Dufour are described: hirtus from Saskatchewan, Ontario, Quebec, and New York, pilipes from New York, and punctatus from Utah. A lectotype for Xylocoris discalis (Van Duzee) is designated. Scoloposcelis mississippensis Drake & Harris and S. occidentalis Drake & Harris are synonymized with S. flavicornis Reuter. Adults of new species are illustrated and electron microscope photographs of their osteolar canals, and that of flavicornis are included.

Eight species of hymenopterous parasitoids were reared from field-collected house fly puparia. The three most abundant parasitoid species, Spalangia nigroaenea Curtis, S. endius Walker, and Muscidifurax raptor Girault and Sanders, were capable of parasitizing up to 90% of hosts at certain times of year. The Spalangia spp. were the most effective parasitoids during most of the fly breeding season. Changes in parasitoid species abundance and rates of parasitism were apparently due to temperature and other habitat conditions.

Two new species of the genus Elatophilus Reuter are described: minutus from Quebec, Ontario, and the Prairie Provinces, Canada, and antennatus from Chiapas, Mexico. Elatophilus vicarius (Drake & Harris) is synonymized with E. inimicus (Drake & Harris). Anthocoris dimidiatus Van Duzee is transferred to Elatophilus. Other species of the genus in North America are oculatus (Drake & Harris), pullus Kelton & Anderson, and pinaphilus Blatchley. A key to known species is given and adults of new species are illustrated.

A frequently used method for determining the threshold temperature for insect development is based on the expression for the hyperbola and its reciprocal (Bean 1961). This method has certain disadvantages, the major one being that the developmental velocity curve is sigmoid and the selection of a linear portion of this curve has a subjective element (Morris and Fulton 1970).

Two new species, Mestocharis nearctica and M. tropicalis (Chalcidoidea: Eulophidae), are described from North America with a key to species and scanning electron microscope photographs. This is the first report of the genus Mestocharis from North America.

Observations of behavior and dissections of hosts were carried out to investigate the ability of Apanteles melanoscelus Ratzeburg (Hymenoptera: Braconidae) to distinguish between parasitized and nonparasitized gypsy moth larvae, Porthetria dispar (L.) (Lepidoptera: Lymantriidae). Fewer host examinations occurred and fewer eggs were laid in hosts which had been parasitized 0–9 days previously than in those which had never been parasitized. However, superparasitism occurred readily especially when few unparasitized hosts were available. By dissecting hosts which were parasitized more than once it was possible to investigate competition between supernumerary parasitoids. First instars are eliminated by some mechanism (possibly active combat), and older parasitoids eliminate younger ones.

When female Tribolium castaneum (Herbst) were sequentially paired with male T. castaneum and then with male T. confusum Jacquelin duVal, 93% of the eggs hatched after the first confinement but only 58.9% hatched after the second confinement. The reciprocal order of pairing produced 0% hatch after the first week of confinement and 55.2% hatch after the second week of confinement. However, the numbers of progeny produced as a result of both sequences were proportional to the percentage hatch. Thus, T. castaneum females appeared to have mated with, and utilized sperm from, males of both species for egg fertilization.

When T. confusum females were sequentially paired in the same way, reductions in egg hatch and production of progeny did not occur. The females either did not mate with T. castaneum males, or if they did mate, they did not utilize T. castaneum sperm for egg fertilization. Moreover the percentage of egg hatch and the numbers of progeny produced were not affected by the sequential order of males as long as one of them was T. confusum.

The previously undescribed adult male and female of Analetris eximia Edmunds are treated. Additional features of nymphs are illustrated. In the Saskatchewan River system the species is found in areas unaffected by reservoirs; nymphs develop in May?, June, and July; adults emerge in late July. Nymphs are carnivorous (chironomids were the main food item in field collected specimens), live in backwaters adjacent to the main river current, and are morphologically adapted to life on an unstable silty substrate. Invasion of the Saskatchewan system was apparently via Missouri tributaries from the Colorado system. It occurred in recent times in the latter but apparently not the former. Because of habitat destruction, the species is considered endangered.

Glypta meritanae, described herein as a new species, parasitizes the larval stage of the white fir needle miner, Epinotia meritana Heinrich, in Colorado and Utah.

The distribution of attack by Scolytus tsugae (Swaine) between and within trees was evaluated in a small, isolated stand of Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) saplings in northern Idaho. Distribution of attacked trees was determined from a complete inventory of the stand Within-tree distribution of attack was evaluated from sample bolts removed from three levels of each of nine sample trees. The infestation was concentrated (> 50%) in the 5-in. (12.7-cm) (dbh) trees during the 3-year outbreak period, but spread to the next smaller and larger diameter classes during the peak year. Approximately 52% of available host trees in each of the 5- and 7-in. (12.7- and 17.8-cm) diameter classes were killed during the outbreak. The lower and middle thirds of the bole sustained the highest number of attacks per ft2 (930 cm2). There was no significant difference in the percentage of successful attacks per ft2 (930 cm2) between tree level; however, the degree of success tended to increase with height in the tree.

Body weight, head width, and cercus length and width of adult male earwigs were found to be polymorphic in both field-collected and laboratory-reared samples. The view that the polymorphisms are the result of environmentally induced ’heterogonic growth’ is discounted. Seasonal, annual, and geographic variation in morph frequencies are demonstrated and discussed.

Laboratory tests showed that the mating frequency of males of Neodiprion sertifer (Geoff.) averaged 4.28 and varied from 0 to 11. A few adults of both sexes did not mate, despite repeated opportunities. As many virgin as mated females oviposited, but virgins laid 19% fewer eggs. Progeny sex ratios were independent of the number of previous matings by the parental male, but apparently were inversely related to the male’s mating ability and may have been determined paternally.

First-stage forest tent caterpillar larvae were tested for the presence of active and sluggish behavior types such as Wellington found in Malacosoma californicum pluviale (Dyar). Larvae capable of directed movement towards a 30 w light source were classified as active. Larvae were tested on 3 consecutive days, and only a small percentage responded on all 3 days. A much larger percentage remained sluggish throughout the period. Chi-square tests confirmed that the differences in response were not random. There was a tendency for some larvae to respond to light during the test and for others not to respond. The reduced consistency in the response of "active" larvae in M. disstria Hübner compared with that reported for M.c. pluviale may be partly due to real behavioral differences, but it also may be partly due to some procedural differences between our tests and Wellington’s.