During 1965–66, studies of a large population of Hylastes nigrinus (Mannerheim), breeding in roots and stumps of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, killed by Dendroctonus pseudotsugae Hopkins in 1964, were conducted on Marys Peak in western Oregon, near the city of Corvallis.

The emergence and flight of H. nigrinus were at their maximum in late April and early May. Emergence was strongly influenced by temperature and seldom occurred at temperatures below 61° and above 75°F. Flight behavior was strongly affected by light intensity, peaking at intensities between 300 and 1200 ft-c during the late afternoon or early evening. Maturation feeding was found to take place on small roots of dead, old Douglas-fir and on roots of young Douglas-fir weakened after replanting. Egg-galleries, normally running parallel with the grain of the wood, were initiated in June and eggs were kid from the end of that month. Five larval instars were found. Adult beetles as well as full-grown larvae overwintered in the galleries. The majority of the population completed development in 1 year.

The larval population of H. nigrinus was heavily decimated during the fall of 1965 by larvae of the dipteron fly, Medetera vidua Wheeler (Doliohopodidae). Emergence data are presented for scolytid, curculionid, cerambycid, and buprestid species competing with H. nigrinus in stumps or roots.

Hylastes nigrinus (Mann.) is attracted to, and breeds in, the roots of both cut and beetle-killed Douglas-fir trees; the latter are preferred. The beetles reach the roots by digging through the soil. Bark samples taken from trees of various physiological condition and placed in field olfactometers showed that the beetle prefers the bark of insect-killed trees, although bark taken from healthy Douglas-firs became attractive after some time. Among the various terpenes tested, α-pinene and β-pinene were most attractive, in addition to Douglas-fir resin itself.

The bark-beetle genus Cactopinus, containing seven species, is reviewed. Distributional data, biological notes, a discussion of each species, and a key for the separation of all species are included. New species are: C. desertus (California) and C. depressus (San Luis Potosi, Mexico). C. cactophthorus Wood and C. mexicanus Wood are placed in a new genus, Cactopinorus.

The Nearctic species of Diadegma that have the abdomen compressed and the propodeum produced beyond the base of the hind coxa are treated as a complex composed of three species groups. A key to groups and species is provided. Two previously described species, D. stenosomus (Vier.) and D. aestivalis (Vier.), and ten new species are described and discussed from the standpoint of their taxonomy, distribution, and host relationships.

The use of false-underground hives (surface hives with tunnels attached to their entrances) when and where the desired species of bumblebees were common made the task of obtaining colonies for pollination purposes comparatively easy. False-underground hives were much less costly to set out than underground hives and attracted many more queens of surface-nesting and versatile species, as well as underground-nesting species, than did surface hives. Apparently the surface-nesting species will accept a nest that is entered through an upward-sloping tunnel but not one that must be reached through a downward-sloping tunnel; underground-nesting species require a tunnel but are not influenced by the direction of its slope.

Setting occupied hives on posts with moats protected the queens or their broods from flooding, ants, ground squirrels, skunks, mice, shrews, and ungulates, but not from Psithyrus, even when odoriferous substances were put in the moats to mask the odor of the broods.

A brief historical review of the occurrence of the clear-winged grasshopper, Camnula pellucida (Scudd.), is presented as well as recent information pertaining to the biology of its various life stages. In the egg stage, diapause is more successfully terminated by chilling at 5 °C for 70 days than at either 0 or −7 °C. Embryological development proceeded very favourably at incubation temperatures of 30 °C while 35 °C produced excessive mortality especially to pre-blastokinesis embryos. Most embryos in eggs of this species reach the same pre-blastokinesis stage of development more consistently every year than do those of other pest species of grasshopper in Saskatchewan. Thirty days of chilling at −12, −18, and −23 °C reduced the viability of the eggs by about 10, 20, and 50% respectively. Exposure to −29 °C killed all eggs in 3.5 to 5 hours.

The phototactic and thermokinetic reactions of nymphs and adults, leading to aggregation, basking, and dispersal, are discussed and compared with those of other species. Details of nymphal migrations are described and related to such meteorological factors as wind, temperature, and position of the sun. Some further details of mating and oviposition are described, especially aggregation on egg beds and oviposition in stubble fields. Observations of predation by sandhill cranes and skunks are also recorded.

The San José scale, Aspidiotus perniciosus Comstock, died within 8 to 22 weeks on McIntosh, Red Delicious, Common Delicious, Winesap, Rome Beauty, and Newtown apples harvested on commercial picking dates and placed in standard cold storage. The scale died in much shorter periods on early maturing varieties than on late maturing varieties.

The later a variety was harvested the longer the fruit had to be stored to kill the scale. The maximum storage period was 32 weeks for Winesaps and Newtowns harvested in early November, approximately 1 month after the commercial picking date.

The storage period required to kill the San José scale on Winesap apples varied from year to year, cool weather in early autumn apparently increasing the storage period.

The pre-storage treatment of fruit with either an antiscald inhibitor or an alcohol solution for segregating water core apples, increased the rate of mortality of the San José scale, Aspidiotus perniciosus Comstock, on Winesap apples held in storage.

The dewaxing and waxing process had little effect on the mortality of the San José scale. The process mechanically removed the scale from the cheeks and shoulders of stored apples but not from the calyx and stem ends.

Woodpeckers consume wood-boring larvae of families Siricidae and Melandryidae leaving three distinct types of mark on the tree. The distribution of marks in relation to decreasing prey population indicates that tapping is the principal means of locating larvae. Forty per cent of siricids and two per cent of melandryids are consumed by woodpeckers on individual feeding trees; as siricid population increases the proportion of larvae taken decreases.

Development time decreased with each increase in rearing temperature in Aedes vexans, A. nigromaculis, and Culiseta inornata until the optimum survival temperature was reached. The optimum survival temperature for A. vexans was 26.5 °C, for A. nigromaculis 21 °C, and for C. inornata 21 °C. Dry weight gain per hour in female larvae was greater than in male larvae in all three species, at all temperatures. There was a significant reduction in weight in each larval instar, pupal, and adult stage, with each 5.5 °C increase in rearing temperature. Times to larval–pupal ecdysis and pupal–adult ecdysis were the same for males and females of A. nigromaculis at all developmental temperatures tested. Time to larval–pupal ecdysis and pupal–adult ecdysis in A. vexans and C. inornata occurred 1 to several days later in females, depending upon the developmental temperature. In all three species the duration of the fourth instar was longest and the specific weight gain greatest.

Capric acid added to a food – whole wheat flour and dried brewers’ yeast – to constitute 2.5% or more of the foodstuff killed all Tribolium confusum Jacquelin du Val within 8 weeks. Lesser amounts of capric acid resulted in different degrees of mortality. By the end of 4 weeks similar results were inevitable when varied levels of capric acid were added to two representative dehydrated foods, tapioca pudding and macaroni and cheese. This uncustomary use of a long-recognized insecticidal fatty acid has some merit: for immixed with foodstuff it can control insect pests, and yet it, as a natural constituent of milk etc., is no stranger to metabolic systems of higher animals, so probably is not too hazardous to humans.

High winter mortality of eggs of three species of grasshopper occurred at various locations in Saskatchewan. Climatological factors associated with these mortalities indicated that egg survival during the winter is dependent upon snow cover as well as upon the intensity and duration of periods of subzero air temperatures.

A new species, Geotrupes (Geotrupes) fisheri, from Nevada de Golima, Jalisco, Mexico, is described and compared with the related Geotrupes cavicollis Bates. Figures and a description of the larva of Ceratotrupes bolivari Halffter and Martinez are included, along with notes on its biology.

Volume 99, 1967

Page 720, lines 4 and 5 from bottom of page, delete Type described from Dahurien (Kentei-Gebirge and Apfel-Gebirge) collected by Radde.