The temperature-dependent rate of development of the post-diapause larval and pupal stages of the spruce budworm parasitoid, Apanteles fumiferanae Vier., was estimated under controlled conditions. Parasitoid larvae required 289.0 degree-days (DD) above a threshold of 8.1 °C to complete development and the pupae required 106.2 DD above a threshold of 9.6 °C to complete development. Longevity of the adult wasp at several temperatures also was examined. Female wasps lived longer than male wasps at all temperatures. Wasps tended to mate more readily under natural than under artificial light conditions.

Newly emerged female A. fumiferanae had few, if any, mature eggs in their ovaries. The number of mature eggs increased to a peak of 40–75 eggs, 4–12 days after eclosion of the adult. The pattern in number of ovipositions was similar to this pattern of egg availability. The daily rate of oviposition, however, was only about one-quarter the number of eggs available.

These biological measurements are discussed in view of the development of a mass-rearing technique for this parasitoid.

A survey of grasshopper populations in Saskatchewan and Alberta indicated that the fungal disease caused by Entomophaga grylli (Fresenius) pathotype II was present in melanopline grasshoppers in 1985 and 1986. The disease was more prevalent and widespread in 1986, being found at 44% of 128 survey sites in Saskatchewan compared with 11% of 190 sites in 1985. In Alberta a high incidence (≥ three per 100 m2) of infected grasshoppers was found at 6% of 1746 sites in 1986 as compared with less that 1% of 2055 sites in 1985. Levels of infection based on cadaver densities at sites with high incidence of disease in Saskatchewan were similar in both years ranging from 3 to 28% for the total population. Melanoplus bivittatus (Say) was the predominant host species for E. grylli pathotype II; M. sanguinipes (Fabricius) was less affected. Entomophaga grylli pathotype I was isolated from Camnula pellucida (Scudder) hosts from a few sites in both Saskatchewan and Alberta in 1986.

Two different species of Tinocallis were previously confused under the name T. saltans (Nevsky). The status of the true T. saltans is established by designation of a lectotype from the Nevsky syntype series. The alate vivipara, embryo, alatoid nymph, male, and ovipara of T. nevskyi sp. nov. are described and compared with T. saltans. The new aphid is known from Iran, Pakistan, and Afghanistan and it recently appeared in Europe. A new synonymy is established: T. yinchuanensis Zhang, 1980 = T. saltans (Nevsky, 1929).

A standardized bioassay procedure was used to determine median lethal doses (LD50) of the microsporidium, Nosema fumiferanae (Thom.), on newly molted fourth- and fifth-instar eastern spruce budworm larvae (Choristoneura fumiferana (Clem.)). The LD50 for fifth-instar larva was 1.23 × 106 ± 2.82 × 105 spores. The fourth-instar LD50 was 2.23 × 104 ± 4.30 × 103 spores per larva for populations experiencing prolonged post-diapause cold storage or an elevated temperature during diapause and 2.00 × 105 ± 6.66 × 104 spores per larva for populations not experiencing stressful conditions during and after diapause. Median lethal times (LT50) ranged from 6 to 19 days, depending on instar and dose level. Sublethal responses of fourth- and fifth-instar larvae inoculated with serial dilutions of spores were estimated by significant linear models. These regressions were negative for pupal weight and adult longevity and positive for development time (duration of instar VI). Inoculations of newly molted sixth-instar larvae produced similar models, although development time was not significantly affected. Insects reared following stress during and after diapause had consistently longer developmental times. The importance of prolonged developmental time on disease expression and insect susceptibility is discussed.

Two new species, Tachinus beckeri from northwestern British Columbia and southern Yukon Territory and T. californicus from southern California, are described and their major diagnostic characters illustrated with line drawings and scanning electron photomicrographs. Tachinus jacuticus campbelli is placed in synonymy with T. jacuticus jacuticus and a new subspecies, T. jacuticus ullrichi, from Quebec and Labrador is named. Tachinus thruppi Hatch is removed from synonymy with T. frigidus and considered a valid species. Both T. thruppi and T. frigidus are redescribed and illustrated. A new, revised key to the species of Tachinus is included.New distributional data are presented for 40 species and new or revised distributional maps are presented for 24 species. Changes in classification of Tachinus proposed by Ullrich in his revision of the world species are reviewed and those that are accepted are incorporated into a revised classification of the North American species. These changes are included in a check list of the North and Central American species of the genus.