Similar percentages of parasitized adults and of females of Phyllotreta cruciferae (Goeze) were collected in traps baited with allyl isothiocyanate and in a D-Vac vacuum insect net early in spring and in August–September, when non-reproducing adults predominated. In contrast, a lower percentage of parasitized adults and a higher percentage of females were collected in the traps than in the D-Vac during the beetles’ reproductive period, May–July. A similar difference between the traps and D-Vac was recorded for Phyllotreta striolata (F.) during April–May, when this species begins to reproduce. Therefore, the results indicate that traps used in this study are unsuitable for measuring parasitism and sex ratio of reproducing P. cruciferae and P. striolata.

One hundred and ten species of insects together with unidentified spiders and pseudoscorpions were collected in foliage samples of Pinus radiata taken from the three natural mainland populations and two planted populations in California. The diversity of the arthropod community in the crowns of P. radiata D.Don was low with 76% of the total number of individuals accounted for by five species groups and 88% by 11 species groups. Spiders were the most abundant species group, comprising 33% of the total number of individuals. The most abundant insect groups were Homoptera, Hemiptera and Coleoptera, respectively. The natural stands supported more species at higher population levels than the planted stands which supported only two species at very high population levels and the rest at low levels. The arthropod communities at the borders of the natural stands were more diverse than at the centers of the stands. The degree of similarity between the natural stands seemed to reflect their geographic distribution; Ano Nuevo and Monterey were most alike and the differences between Ano Nuevo and Cambria were greater than those between Monterey and Cambria. Differences in insect communities within and between the natural and planted stands are discussed in detail.

In direct contact toxicity tests with four pyrethroid and three standard insecticides, using 24–48 h old crickets, Acheta pennsylvanicus (Burmeister), as test insects, carbofuran was most toxic > cypermethrin > fensulfothion > chlorpyrifos > fenvalerate > fenpropanate > permethrin. In moist (5% water) Plainfield sand, using the same test insect, chlorpyrifos was most toxic > carbofuran > fenpropanate > cypermethrin > permethrin > fenvalerate > fensulfothion, i.e. the pyrethroids, although quite strongly adsorbed by soil, were still moderately active as soil insecticides. All pyrethroids were less toxic in muck soil as compared with Plainfield sand, and in air-dry (0.5% water) as compared with moist (5% water) Plainfield sand, with the effects being less on cypermethrin and fenvalerate and greater on permethrin and fenpropanate. None of the pyrethroids was affected by soil type and moisture to the same extent as was carbofuran. Permethrin, fenvalerate, and cypermethrin showed a negative temperature coefficient of toxicity in moist Plainfield sand, being from 1.4 to 1.9× more toxic at 15° than at 32°C. Fenpropanate, like carbofuran, was slightly more toxic at 32° than at 15°C. Generally, soil type, moisture, and temperature had minimal effects on the toxicity of the four pyrethroid insecticides. In persistence studies over 48 weeks, using Plainfield sand, the pyrethroids were more persistent than chlorpyrifos, but less persistent than dieldrin. Under these laboratory conditions, permethrin and fenvalerate were slightly more persistent, while fenpropanate and cypermethrin were as persistent as carbofuran. Trans-isomers of permethrin and cypermethrin declined more quickly in the sand than did the cis-isomers and of the trans-isomers the 1S,trans declined much faster than the 1R,trans while little difference was observed for the corresponding 1S- and 1R,cis-isomers.

When male drone flies (Eristalis tenax (L.)) of the spring and summer generations stop dispersing, they settle within individual home ranges that provide them with sheltering, resting, basking, grooming, feeding, and mating sites. Away from its mating place, a resident male rarely responds to other insects. On its mating site, however, it is territorial, attacking alien species, such as bees, wasps, and butterflies, as well as conspecific intruders. Territorial duty is demanding, and resident males take rest periods outside their territories whenever they can. When prevented from doing so, either by sky conditions which confine them to the territory, or by crowding which eliminates many neutral sites, they become increasingly aggressive. Males on open, horizontal territories (e.g., in flowerbeds) are more likely to notice intruders, and therefore are more liable to attack them, than males on vertical territories (e.g., on broad-leaved shrubs). The aggressiveness of E. tenax has social and ecological ramifications beyond its own species, since bees may stop foraging and aphidophagous syrphids may not oviposit in places where drone flies are exceptionally active.

Bran treated with four different insecticides was field-tested as a crop protection measure against mainly third instar grasshopper populations composed mostly of Melanoplus sanguinipes (Fab.). The order of toxicity of these four insecticides was dimethoate 〉 fenvalerate 〉 propoxur 〉 pyridaphenthion. Five dosages of dimethoate were tested against mainly adult grasshopper populations. Rates of mortality due to both aqueous sprays (previously published results) and bran baits were compared. Degradation of both dimethoate and fenvalerate mixed with bran was small when stored in the laboratory at either 1°C or 20°C.

All stages of a new genus, Euryhapsis, are described and differentiated from several other genera of primitive Orthocladiinae. Three new species are described: Euryhapsis cilium (type-species), Euryhapsis illoba, and Euryhapsis brevis. Eurycnemus annuliventris (Malloch) is transferred to Euryhapsis. A key to species of males is presented.

The genus Thripoctenoides (subfamily Entedontinae: Eulophidae) is recorded from North America for the first time, and Thripoctenoides kaulbarsi, new species, is described.

Dissections of eggnests of brood XIV, 17-year periodical cicadas (Magicicada spp.) confirmed earlier reports that most eggs do not hatch when the host twig is so damaged that it withers, breaks and dies, i.e., “flags”. However, the proportion of eggs hatching in experimentally broken twigs is intermediate between the proportions hatching in flagged twigs and in live twigs. Evidently, the developmental stage of the egg at the time of twig breakage is the major factor reducing hatching success.

Some of the vigorously growing branches respond to oviposition damage by secreting resin or forming callous tissue, which imprisons many eggs, preventing them from hatching. The data suggest that ovipositing cicadas have developed an oviposition strategy that both maximizes the number and percentage hatch of eggs laid per twig, and reduces the incidence of flagging and host defence responses. Large aggregations of ovipositing females may weaken the host plant and prevent it from responding. On the other hand these aggregations increase twig breakage. However, the proportion of twigs broken is reduced by each cicada species using somewhat different twig sizes, by the smaller species adjusting eggnest structure to fit the twig size used, and by all females positioning their eggnests along the twig in such a way as to avoid overlap.

The fecundity, survivorship, and rate of development of the lupine aphid Macrosiphum albifrons Essig were determined and summarized into life tables from which the intrinsic rate of increase was computed. The life tables, using a time scale in days, were converted to a variable life table model using a physiological time scale based on an estimated thermal threshold of development of 3.59° (± 0.587°). A method of determining age and fecundity of adult aphids was developed from weight and embryo content. The use of intrinsic rate of increase and of the method of aging in field population dynamics are discussed.

Two new species of Lygaeinae are described from Canada. Lygaeospilus brevipilus from British Columbia and Melanopleurus perplexus from Alberta, Manitoba, and Saskatchewan. L. brevipilus is also recorded from Oregon. The record of M. perplexus in Canada represents an extension of the previously recorded range for the genus Melanopleurus. Revised keys to the species of Lygaeospilus and Melanopleurus are given.

Confined to the nearctic region the Myrmica lampra group includes two related species without worker caste that probably live as parasites in the colonies of Myrmica alaskensis. The morphological characteristics of this new group are given, and a new species, M. quebecensis, is described. The taxonomic relationships of the group within the genus are discussed; they support the conclusion that the palaearctic subgenus Dodecamyrmica must be rejected as artificial.

Many factors have been examined that affect simuliid larval distribution in a stream but little has been published on interspecific competition influencing their distribution. Certain black fly species distribute themselves over a suitable substrate in a regular manner with an open space around each larva. The individuals of these species will strike at others entering within this space resulting in the departure of one or other of the combatants. This establishes a regular pattern of spaced larvae of a certain density, which may be influenced by current velocity, over areas of suitable substrate (Colbo 1979). However, larvae of other species clump without apparent spacing and less readily move when contacted.

Timing traps are widely used to study the diurnal flight activity of insects, their response rhythms to physical and chemical (olfactory) stimuli, and the effect of weather factors on these behaviors. Goetz (1941) used an adhesive-coated horizontal metal disk driven by a mechanical clock to determine the periodicity of male-female attraction in two lepidopterous species on grapes. The area of the disk exposed at any time corresponded to a 1-h sector of the clock dial. The disk completed a full revolution every 12 h and therefore the trap had to be checked twice a day. Also, since the clock speed was not variable, the trapping interval could only be adjusted by decreasing or increasing the opening to the sticky disk.

Larvae of the sawfly genus Gilpinia Benson, a Palaearctic genus, attack conifers. Smith (1974) listed 24 species, two of which, G. frutetorum (Fabricius) and G. hercyniae (Hartig), were accidentally introduced into North America. Keys to known species of Gilpinia have been published for adults (Enslin 1917; Takeuchi 1940; Gussakovskij 1947; Berland 1947; Benson 1951; Okutani 1958) and for most European larvae (Lorenz and Kraus 1957; Běnes and Kristek 1979).

The author (1977) reported on 10 species of insect parasites that were reared from field-collected larvae or pupae of the darksided cutworm, Euxoa messoria (Harris), in Ontario. Of those, eight species had not been previously recorded from this host. During subsequent studies at Delhi, Ontario in 1976 and 1977, more than 3000 larvae of this cutworm were collected from rye and tobacco fields and reared in the laboratory, using methods previously described (Cheng 1977). From this work four more species of primary endoparasites were newly recorded, namely, Apanteles laeviceps Ashmead (Braconidae), Apanteles militaris Walsh (Braconidae), Campoletis sp. (Ichneumonidae), and Meteorus communis (Cresson) (Braconidae). Arenetra sp. reported in the earlier work appeared again and was determined to be A. rufipes vernalis Walley (Ichneumonidae).

The egg parasite Ooencyrtus ennomophagus Yoshimoto (1975) is a good candidate for the biological control of certain defoliators. In 3 years it eliminated an outbreak of the elm spanworm, Ennomos subsignarius (Hübner), that reached from southeastern New York State across Connecticut and into Rhode Island (Kaya and Anderson 1974). Timely biological control, however, requires maintenance of parasite cultures in a laboratory for mass production when the need arises. Adults of O. ennomophagus live for about 3 months in the laboratory, but supplying them with suitable host material has been a problem. Drooz and Solomon (1980) found that the eggs of the factitious host, the notodontid Clostera inclusa (Hübner), could be stored at −10°C for a month and used for culturing O. ennomophagus. Tests under way indicate that the eggs may be stored longer than 12 months. I report here the development of O. ennomophagus in eggs kept at −10°C but not in fresh eggs of the pine looper, Lambdina pellucidaria (Grote and Robinson). The results indicate a potential for rearing parasites on treated eggs of non-host insects, if the need arises.