Females of Nasonia vitripennis (Walk.) (Hymenoptera: Pteromalidae) discriminate between unparasitized housefly pupae (Musca domestica L.) and those parasitized by either Muscidifurax raptor G. & S. or Spalangia cameroni Perk. (Hymenoptera: Pteromalidae) and lay fewer eggs on parasitized hosts. Oviposirion restraint is more pronounced towards hosts attacked by M. raptor than towards those attacked by S. cameroni, but less than that exhibited towards pupae previously parasitized by N. vitripennis. Damage to the fly pupae, from piercing by the female’s ovipositor and probably also from a "venom" injected by the female, is responsible for inter- as well as ultra-specific discrimination and restraint.

A new species of Egnatioides (Orthoptera: Acrididae) is described, E. lizae, from Paktia Province, Afghanistan.

Penetration of topically applied DDT-C14, at dosages varying between 35 and 2900 nanograms, into individual house flies was studied at 2, 6, and 24 hour intervals. The rate of penetration was found to be dose dependent and not exponential even when nanogram quantities of the chemical were used.

Flight orientation about the yaw axis (induced by rotation of a striped bowl) in the squash bug, Anoplecnimes curvipes (Heteroptera), is brought about by differential changes in wing-stroke amplitudes and wing-stroke planes of the two sides. The metathoracic leg of the inner side in a turn is displaced in the transverse plane while the contra-lateral leg remains in the normal flight posture. The probable mode of control of the two wing parameters effecting yaw is discussed.

Species of the North American genus Platylygus Van Duzee 1915 are revised. Redescriptions are given for 5 previously known species, and 26 new species are described. Nineteen species described by Kelton are: angulatus, brevirostris, longirostris, and mexicanus from Durango, Mex.; aztecus from Mexico, Mex.; chamulans and chiapasensis from Chiapas, Mex.; alpinus from Chiapas, Mexico, and Puebla, Mex.; crassicornis from Mexico and Puebla, Mex.; pilosus and teocotae from Mexico, Mex.; pilosipes from Durango, Mex., and Arizona; scutellatus from Durango, Mex., Arizona, and New Mexico; contortae, crinitus, and magnus from California; knighti from Arizona and Colorado; piceicola from British Columbia, Yukon Territory, Arizona, and Colorado; pseudotsugae from British Columbia and Oregon. Seven species described by Knight are: keltoni from Durango, Mex.; andrei from Arizona; balli from Arizona, Colorado, and New Mexico; hirtus from Arizona; rolfsi from British Columbia, California, Oregon, and Washington; rubripes from Alberta, British Columbia, California, Colorado, Oregon, and Wyoming; and usingeri from California. The other species in the genus are: fuliginosus Knight from Arizona; grandis Knight from Arizona, California, and Colorado, Montana, and South Dakota; intermedius Knight from Arizona, Colorado and New Mexico; luridus (Reuter) from Alberta, British Columbia, Manitoba, New Brunswick, Nova Scotia, Ontario, Quebec, Saskatchewan, Yukon Territory, Arizona, Colorado, Illinois, New Hampshire, New Mexico, New York, and Wyoming; and vanduzeei Usinger from Arizona, California, Colorado, New Mexico, Nevada, and Utah. Platylygus uhleri (Van Duzee) is considered to be a synonym of P. luridus (Reuter). A key to species, records on distribution and biological data are included, and the male genitalia of all but one species are illustrated.

An investigation of the life-history and habits of Ips cembrae (Heer) has been made at the Ord wood, Cawdor Estate in Nairnshire. The species is polygamous and has a 1-year life cycle with two broods a year. The first broods result from eggs laid in May and June, producing teneral adults in August and September, and the second arise from egg-laying in late September and early October; these second broods generally overwinter under bark in the larval and pupal stages, and the adults emerge the following spring. There are three larval instars before pupation. Maturation feeding of the young beetles and regeneration feeding of the old ones take place either under the bark where broods have developed, or by attacking fresh host trees.

The apple aphid population density on 1-year-old trees under controlled conditions of decreasing temperatures and photoperiods equivalent to 1 August through 14 November 1967, remained almost static up to the time of apple tree defoliation. Alate forms disappeared and reproduction levelled off after a 13.3 hr, 17 °C light, and a 12 °C dark temperature were programmed. Aphids left the apex of the tree after vegetative growth ceased and became distributed more or less evenly over the older leaves. Egg deposition occurred after the photoperiod became shorter than 11.8/24 hr and temperatures less than 12 °C during the light period, 8 °C during darkness. This "autumn population" of aphids with no external detrimental biotic or extreme climatic effects produced winter eggs equal to one-third its numbers at the time of beginning oviposition.

Cultural practices, temperature, and precipitation affect the population fluctuations of Hylobius pales (Herbst) in the piedmont of Georgia. Of the environmental factors, temperature appears to have the most decided influence on the seasonal activity of the weevils. Precipitation may cause some variation but has no effect on general population trends. Cultural practices affect the numbers of weevils collected but not the seasonal trends. Although weevils are long lived and oviposition and larval development occur almost continuously, there are two population peaks during the year.

Biological data are given for Coeloides pissodis (Ashmead), Dendrosoter sulcatus Muesebeck, Heterospilus sp., Spathius pallidus Ashmead, Eurytoma conica Provancher, Cecidostiba polygraphi Ashmead, Heydenia unica Cook and Davis, Roptrocerus xylophagorum (Ratzeburg), Rhopalicus pulchripennis (Crawford), Rhopalicus tutela (Walker), and Tomicobia tibialis Ashmead. Only Coeloides pissodis was always closely associated with its host. The other larval parasites were often found disassociated from any host, suggesting an ability to seek out hosts in Ips galleries and the potential to attack more than one host. Observations indicated that pupal parasitism may be significant. Comment on the potential of some parasites as control agents is included.

Biosynthesis by the larva of the dipeptide β-alanyl-L-tyrosine may be a useful taxonomic criterion for distinguishing members of the genus Sarcophaga. An application of this criterion to a sarcophagid parasite (currently known as Pseudosarcophaga affinis auct. nec Fallén) of controversial taxonomic and nomenclatural history is illustrated.

Notes on the biology and habits of 12 parasitic insects associated with Eucosma rescissoriana Heinrich in western white pine, Pinus monticola Douglas, cones in northern Idaho are presented. Descriptive notes on the immature stages of three important parasite species. Chelonus petrovae McComb (Hymenoptera: Braconidae), Apanteles starki Mason (Hymenoptera: Braconidae), and Psalidopteryx psilocorsiphaga Brooks (Diptera: Tachinidae) also are included. Correlations between the life stages of these three parasite species are made with phenological events in the host tree and associated plants at two of the four study plots.

The "secondary" attraction occurring after log attack by the female ambrosia beetle, Trypodendron lineatum (Oliv.), and the reduction in attractiveness after males arrive on the log are not dependent directly on mating. The reduction seems to be associated with the males’ presence, which suggests that they produce a masking substance.

A new host record for the sawfly Monostegia abdominalis (F.) was obtained in Quebec. The host plant, terrestrial loosestrife (Lysimachia terrestris (L.) BSP), was abundant on a lake shore due to regular flooding, enabling the sawfly to reach a high population level. Two generations occurred each year. The immature stages and aspects of their behaviour, and female oviposition behaviour, are described.

Adults of the web-spinning sawfly Pamphilius ochreipes (Cresson) have been collected widely in North America in the past. The immature stages and food plants were unknown until a recent study was made in southern Ontario where the larvae fed in leaf rolls on cultivated Viburnum opulus L., in June. The sawfly is univoltine and overwinters as a larva in the soil with adult emergence in late May and early June.

An unique development in insect dietetics is announced, namely, the rearing of an hymenopteran — Itoplectis conquisitor (Say), an ichneumonid endoparasitoid of other insects — axenically on a chemically-defined synthetic diet. First heuristic attempts produced a yield of about 17% adults.

The occurrence of Dioryctria ametella (Hulst) (Lepidoptera: Phycitidae) as well as several other insect inhabitants of Cronartium fusiforme Hedgc. and Hunt cankers was investigated. A species of Pissodes (Coleoptera: Curculionidae) and Eurytoma sciromatis Bugbee (Hymenoptera: Eurytomidae) were found to be winter inhabitants of the cankers. The importance of the cankers as an overwintering habitat for D. amatella was also considered.

Life histories of Conophthorus beetles attacking the shoot tips of jack, red, Scotch, and ponderosa pines were studied and compared with the life history of the red pine cone beetle, Conophthorus resinosae Hopkins. The tip-infesting beetles have not been morphologically separated from C. resinosae. The beetles attacking the shoots of jack, red, Scotch, and ponderosa pines have similar life histories which differ from that of C. resinosae. The latter is distinctly univoltine, while the tip-infesting beetles appear to be bivoltine. Also, dates of appearance and seasonal development differ.

Controlled mating experiments demonstrating total reproductive isolation, together with consistent differences in morphological and cytological detail, confirmed the validity of the closely related group IX Ips: grandicollis, cribricollis, lecontei, montanus, confusus, paraconfusus, and hoppingi. The latter two species, new to science, were formerly considered to be confusus.Matings between grandicollis from eastern Canada and North Carolina were subnormally fertile; other intraspecific matings between individuals of the same population or distant populations produced fully fertile progeny. Interspecific pairings usually resulted in insemination and normal-appearing egg galleries, but, with one exception, none of the eggs hatched.One montanus and two confusus, each mated by males of the same species, produced all-daughter broods. This "sex-ratio" condition appeared to be the result of a matrilineally transferred cytoplasmic factor lethal to male embryos only.At first meiotic metaphase all species had the karyotypic formula 15 AA + Xyp, and only grandicollis was easily differentiated by bivalent configuration or size sequence. Most other species showed diagnostic differences at meiotic prophase or second meiotic metaphase. Pairing disruptions and anaphase bridges occurred in grandicollis interpopulational hybrids; meiosis was normal in progeny from interpopulational pairings of confusus, paraconfusus, and montanus.In grandicollis the median struts of the male genitalia were 1.5 times longer than the median lobe. The struts/lobe ratios for other species approximated 1.00 but differences for most comparisons between species were statistically significant. The shape of the pars stridens on females was different for most species and mean widths of striations thereon ranged from 0.517 μ for paraconfusus to 0.876 μ for lecontei. This character provided absolute discrimination of females of confusus from those of paraconfusus and hoppingi but the latter two species were most easily separated by differences in the density of punctures in the elytral declivity.It is hypothesized that contiguous allopatry and differences in host and ecological specialization, evidenced in species of group IX, is maintained by their high propensity for interspecific mating which fails completely to produce progeny.