Almost 40% of the cells of Megachile rotundata (F.) from the earliest completed tunnels in the hives produced as second-generation bees. This percentage rapidly decreased in the later completed tunnels. The difference between wing venation of bees that emerged in spring and of second-generation bees that emerged in summer appears to be related to voltinism.

Distributional and anatomical characteristics of the species of the western North American genus Cordylospasta are analyzed. The current concept of this genus is a considerable modification from that of earlier classifications.

Of the two species belonging to Cordylospasta, C. fulleri Horn is unique among North American blister beetles in having antennae with 8 to 10 antennal segments. This species is strictly allopatric to the second species, C. opaca (Horn), in which the antennae are 11-segmented.

Step-clinal geographic variation in seven anatomical characters is recorded for C. opaca. On this basis six biological races are recognized as occurring in central and southern California. These are considered the equivalent of subspecies. An informal approach to the recognition of these infraspecific taxa is followed since, due to limited material, interracial reproductive relationships cannot be inferred confidently at the present time.

The female and male of Tarsonemus granarius n. sp. are described and illustrated. This mite occurs in granaries in Canada, Japan, and the British Isles. It feeds on, and perhaps disseminates, fungi that deteriorate grain stored for prolonged periods. Similarities and differences in the morphology and ecology of adults of this species and of T. fusarii Cooreman are discussed.

Endecascelio stipitipennis n. gen. and n. sp. is described from Central Africa (former Belgian Congo). The extent and interrelationships of the tribe Embidobiini are discussed. A diagnosis of the tribe and a key to genera of the world is given.The genus Embidobia Ashmead is for the first time reported from the Oligocene of Baltic amber.

Soaking shredded moss and birch bark samples in a 2% bleach solution for 45 minutes will release attached hemlock looper eggs. Soaking has no deleterious effect on the hatching of larvae or the emergence of parasites. This technique, in contrast to direct examination, results in a significant increase in the number of eggs obtained and a decrease in counting time. It also permits the development of egg sampling techniques for use over extensive areas and the collection of eggs in large numbers.

Coeloides brunneri Viereck females were interrupted in the act of oviposition into Douglas-fir logs and the oviposition site marked. Thermistor probe temperature readings revealed that C. brunneri invariably oviposited over "hotspots" on the bark surface associated with subcortical Douglas-fir beetle larvae. Artificial hotspots were created by placing heated resistance wire probes underneath the bark of an uninfested log. In the absence of all other stimuli, these artificial hotspots induced the parasites to exhibit normal search behavior and to make ovipositional probes, the final phase of host finding. These data augment observations of antennal posture of a searching parasite and the discovery of a possible infrared radiation receptor on the antennae, and support the argument that C. brunneri locates its host through perception of infrared radiation.

Haemocytes are described and illustrated for 16 species of cockroaches, and data are given on haemocyte size and numbers. Each family in the suborder Blattaria is represented. In all of the species, the haemocyte complex comprises plasmatocytes and granular haemocytes in addition to mainly germinal elements, the prohaemocytes. Spherule cells, a distinctive form of granular haemocyte, occur in most "modern" species (superfamily Blaberoidea), but are absent from most species in the more primitive group (superfamily Blattoidea). Taxonomic relationships at other levels are reflected particularly in morphological features of granular haemocytes. Although the haemocyte complex alone offers insufficient evidence for systematic arrangement, it provides additional characters for classifying species.

The haemocyte (blood cell) complex in insects has distinctive characteristics at various taxonomic levels. Some taxa can be recognized easily by major differences in the number and size of the haemocytes and the complexity of cell types. Others can be distinguished only with difficulty by means of cytological features of certain cell categories. Still others have revealed no distinguishing characters. The haemocyte complex is potentially useful for indicating some systematic relationships, and in some cases for distinguishing between morphologically similar species. The concept requires careful testing.

Addition of DL-α-tocopherol (vitamin E) at a level of 17.2 μg/g to an artificial diet containing casein, glucose, cellulose powder, salts, cholesterol, and a mixture of B-vitamins results in a loss of pigmentation in 30–50% of males on adult emergence. These albino males are of a light amber colour, apparently lacking melanin, although their cuticle appears to be sclerotized, and their sexual behaviour is normal.

Overwintering eggs of Porthetria dispar increase their capacity to supercool during exposure to non-lethal conditioning temperatures. Measurements of supercooling points of eggs collected in Quebec and Massachusetts indicate that the gradual movement of the insect north and west from the initial point of introduction into North America has not been accompanied by natural selection for a more cold-hardy population. The protection afforded eggs by cold-hardening is, however, greatly enhanced by the placement of egg masses, typically at or near ground level, where they are subject to maximum insulation by snow cover.

Examination of climatic regimes within the current area of distribution of the gypsy moth in Eurasia indicates that temperature may not be a key factor limiting its northward spread. In central Canada, in the presence of abundant snow cover, the insect may spread as far north as suitable food plants exist. This would favour extension of the range of the gypsy moth throughout the Great Lakes – St. Lawrence Forest Region and much of the Boreal Forest Region of Ontario and Quebec south of James Bay.

The paper describes and maps stripe pattern variability in the damselfly Argia apicalis (Say) along the periphery of its southeastern distribution. Two major variations exist. One, the broad-striped form, has a wide, full-length humeral stripe and, in females, a well-developed middorsal thoracic stripe. Broad-striped specimens also possess larger areas of black pattern on the dorsum of the head and, in males, on the eighth and ninth abdominal segments. The second, typical form, has a reduced pattern characterizing populations west and north of southeast Georgia and northern Florida. The southeastern margin of distribution consists of broad-striped populations representing four groups of isolated populations. Isolation results from low interchange between colonies of different river systems and, within the southeast, lack of colonies on lakes, ponds, smaller streams, and river headwaters. One intergradation area between typical and broad-striped populations is known. A discussion follows relating origin of the variability to Pleistocene habitat changes.

Adult Trichoptera of 39 species representing 11 families were collected from 4 emergence traps in Oak Creek, Corvallis, Ore., between May 1968 and December 1970. Glossosomatidae and Limnephilidae were the most abundant families, but Rhyacophilidae was represented by the most species. Relative abundance, seasonal occurrence, sex ratios, and ecological segregation of related species are discussed.

Terrestrial arthropods collected from Bathurst Island in 1969 are listed: 78 species (4 spiders, 13 mites, and 61 insects, 30 of which are chironomids) have now been collected in this area of the high arctic. Notes on the overwintering of some of the commoner insect species are given. Although the collecting season was a poor one in 1969 because of adverse weather conditions, the list probably represents half or more of the island’s arthropod fauna. The nature of the list indicates that this fauna is impoverished compared to some other areas of the Queen Elizabeth Islands. This impoverishment may be largely explained by climatic factors.

Only one parasite species survived on most housefly (Musca domestica L.) pupae multiparasitized by any two of Nasonia vitripennis (Walk.), Muscidifurax zaraptor K. & L., or Spalangia cameroni Perk. N. vitripennis and M. zaraptor were both intrinsically superior to S. cameroni if the attacks on the hosts by their females preceded, were simultaneous with, or followed by up to 48 hours those by females of S. cameroni. N. vitripennis was intrinsically superior to M. zaraptor if its attack preceded that by M. zaraptor by at least 24 hours; M. zaraptor survived when it oviposited before N. vitripennis; and neither species was consistently superior to the other when their attacks were simultaneous or that by N. vitripennis closely preceded that by M. zaraptor. N. vitripennis often survived on multiparasitized hosts because of its rapid development and rapid and thorough host utilization which caused its rivals to starve. In contrast, M. zaraptor’s success was a consequence of its prédation on eggs and larvae of its competitors and to a lesser extent its moderately rapid development and host utilization. S. cameroni was usually intrinsically inferior to both of the other species because, in spite of being predaceous on their larvae, it developed much more slowly and seldom attacked their eggs. The significance of these qualitative characteristics in insect parasites used in biological control programmes is discussed.

Fertility of Achaearanea tepidariorum (C. L. Koch) that were fed mosquitoes chemosterilized by pupal exposure to thiotepa was significantly reduced. Mortality was excessive for spiders fed mosquitoes treated topically with thiotepa. Maximal weekly dosages, estimated by residue analysis, were 12 and 21 ng/male and female respectively for spiders fed mosquitoes treated as pupae and over 3 times greater for spiders fed mosquitoes treated topically as adults. The susceptibility of this predator to small chronic dosages of chemosterilant suggests that mass releases of chemosterilized insects are potentially hazardous to food chain components.

The larch sawfly, Pristiphora erichsonii (Hartig), has exhibited several distinctive population patterns in different parts of its Holarctic distribution and during different periods of time in some geographic areas. These patterns include a latent type, where the larch sawfly is never a pest, a permanent type, which causes severe damage, and several temporary types characterized by periodic outbreaks. The different population patterns are associated with differences in the life systems of the populations: the stable latent type with a diverse environment and a rich parasite complex; the stable permanent type with an impoverished parasite complex, interactions with food availability and no effective specific parasites; and the temporary type with an intermediate parasite complex which includes one very effective specific larval parasite. Thus, population stability is related to either maximal or minimal diversity in numbers of parasite species and instability to intermediate levels. The comparison of population patterns and life systems provides a guide to the development of biological control programs.

Eight new species of Cicadellidae are described, largely from Manitoban material: Macropsis feminis, M. sauront, M. vinea, Gyponana gracilis, Cicadula junea, Laevicephalus bison, Macrosteles (Sagatus) flavalis, and Paraphlepsius varispinus. The male genitalia of Fitchana twiningi (Uhler) is described for the first time. Colour forms of Macropsis nigricans Van D. and Balclutha punctata (Thunb.) are illustrated.

By a method of micro-cauterization, in which a small area of tissue may be destroyed without bleeding, it is indicated that the pigmented areas on the pupa of the monarch butterfly, Danaus p. plexippus (Linnaeus), are involved in the distribution or formation of wing scale colouration. The paper deals with experiments involving one pair of such areas, namely the alar (Al) pigmented macula which, like the median notai macula, effects apical wing colour on the prothoracic wings.

Both males and females of Rhagoletis pomonella (Walsh) showed three distinct modes of aggressive behavior: (1) a wing-waving display, (2) charging headlong into another fly, and (3) "pawing" with the prothoracic legs. The flies were aggressive toward their own and the opposite sex. The aggressive patterns were similar to those of R. suavis (Loew) and R. completa Cresson.