Although adults from each of four study areas in California showed no morphological differences and were identified as belonging to the Neodiprion fulviceps complex, a number of biological differences in different stages of development indicate that there are three distinct populations of one species or subspecies of a species in the, N. fulviceps complex in California.

The life stages are typical of Neodiprion species. Overwintering as eggs, eclosion commences in the spring. The larvae drop to the ground after four to six feeding instars, spinning their cocoons in the duff beneath the host trees. Pre pupal larvae spend the summer in the cocoon; pupation occurs in the fall and adult emergence follows two to three weeks after.

The foliage chosen for oviposition is mainly the current year's growth. Oviposition occurs largely in the upper crown of trees less than 10 feet in height, while in trees larger than 10 feet the lower crown is preferred. The outer two-thirds of the foliage of an individual tip and the lower gravitation edges of needles are favored for oviposition.

Some of the differences supporting the belief that there are distinct species or subspecies include number of eggs per female, number of needles in each fascicle used for oviposition, number of eggs inserted in each needle, spacing of egg pockets, egg color, number of feeding instars, date of larval eclosion, larval size, and larval feeding capacity.

Males and females emerged in synchrony in the laboratory and the field. Males predominated in cocoon collections but females predominated in rearings of larvae. This discrepancy in sex ratio may be due to a differential mortality factor. (In this study no prepupae were found to go into an extended diapause.)

One adult morphological character was found that may be of significance in supporting the contention that distinct populations or subspecies occur. Females in one study area generally had more antennal segments than females in other areas. This character along with the biological differences may prove adequate to describe these populations as subspecies or even species in the future bur it was felt that additional names, at this time, would only add to the confusion in the genus. Such descriptions should wait until the entire N. fulviceps complex can be considered.

Six genera are recognized in the tribe Ammophilini: Ammophila, Podalonia, Eremnophila, Eremochares, Hoplammophila and Parapsammophila. A synonymical species checklist is given for the last three genera. A key to genera is provided which is based partially on characters heretofore unutilized.

The painted leafhopper, Endria inimica (Say), occurs in grasslands in southern Canada and the northern states of the U.S.A. It is the only known vector of wheat striate mosaic virus (WSMV) in North America. In Manitoba the insect is not abundant. It does not migrate into the province, and overwinters in the egg stage only. There are two generations per year, the first completing development on grasses about 1 July and the second developing mainly on cereals in summer. E. inimica has a high rate of development at 90° F.; the lower limit is near 60° F. At 80 ± 5° F. the life cycle was completed in 45.8 days. In the field, in summer, the life cycle was completed in 42 days. A description of the life stages of the insect is presented.

WSMV has occurred only in trace amounts in Manitoba. Leafhoppers collected in the field showed a low frequency of virus transmission and the source of overwintered virus appeared to be small. The disease does not appear to constitute a serious problem in Manitoba.

Kristotomus simplex is described from Japan. It is the most primitive member of its genus and appears closely related to Orthomiscus Mason. A key is given to distinguish the Japanese species of Kristotomus, Orthomiscus, Kerrichia, and closely related forms.

Specifications and construction of an automatically recording insect flight mill are described. Revolutions of individual flight mills are recorded, by means of photocells, on electric counters.

The black-headed budworm, Acleris variana (Fern.), is a forest pest native to North America. Periodic outbreaks have been recorded since the late 1920's in eastern Canada, where the preferred host is balsam fir. An outbreak generally causes 2 years of severe defoliation but no tree mortality and only a slight loss in radial increment.

Color patterns and measurements of the immature stages are given and limited data on age-interval survival rates are discussed. A key-factor analysis of 17 years’ data shows that population release is associated with years of low parasitism and favorable weather, while population decline is largely determined by late larval parasitism.

The species of Bothromus Townes and Townes are discussed from the standpoint of their taxonomy, distribution and hosts; and a revised key to species is presented. Bothromus bicolor n. sp. is described from Alberta, British Columbia, Quebec, South Dakota and Washington.

Full-grown larvae of Zeiraphera pacifica Freeman and Epinotia hopkinsana (Kearfott) are described and figured.

Recent conflicting theories regarding host finding by blood-sucking flies and the mode of action of repellents are examined and discussed. The claim that repellents owe their activity to infra-red absorption in a narrow waveband (449–467 cm.−1) was examined by measurement of published curves for infra-red absorption by repellent, non-repellent, and doubtful chemicals. Peaks of absorption at this waveband in comparison with adjacent Wave numbers are three times as common in repellent as in non-repellent materials, but in comparison with absorption over the entire spectrum studied all groups of materials show a trough of absorption at this narrow waveband. No supporting evidence could be found for the claim that mosquito repellents masquerade as water vapour by virtue of their infra-red absorption spectra, nor for the suggestion arising out of this, that such repellents should be attractive at low humidities. Repellency of indalone was found to increase as humidity decreased.

Regardless of the role molecular vibration may play in olfactory perception, the usefulness of infra-red radiation to blood-sucking flies seeking their hosts and to man seeking repellents for the flies remains to be demonstrated.

The systematic relationships of Sciadoceridae and of the other families of the superfamily Phoroidea, i.e., Platypezidae, Ironomyiidae and Phoridae, are reviewed. A new family, Ironomyiidae, is proposed for Ironomyia nigromaculata White from Tasmania. Two fossil flies in Canadian (Cretaceous) amber, representing two new genera and species of Sciadoceridae, are described and figured. These constitute the first record of the family in North America. The supposed phylogenies of the families of the Phoroidea and of the genera and species of Sciadoceridae are outlined; the evolution and biogeography of the latter family is treated in detail. Keys to the families of the Phoroidea and to the genera and species of Sciadoceridae are provided.

Factors, i.e., time, climate, and isolation, that have or may possibly have influenced the distribution and speciation of Scarabaeidae in North America are discussed. Specific examples of present distributional patterns in the genera Phyllophaga, Serica, Diplotaxis, Onthophagus, Geotrupes and Trox are mapped and described. A general comparison of the distributional patterns is made, and inferences are drawn concerning centers of dispersal and (or) areas of survival of the insect inhabitants of deserts and temperate forests during the various climatic changes of the Pleistocene.

A statistical analysis of U.S.DA. studies of insect attractants provides the first direct evidence for the reality of "primary" odors (heretofore inferred indirectly from abstract principles). Molecules of a single substance may carry more than one primary osmic character and the presence of one does not preclude another, but some primaries may overlap others. Thus the molecular qualities responsible for osmic properties appear to be distributed along a continuum. Molecular vibrational frequencies are so distributed, and the far infrared absorption spectra of some attractant and non-attractant substances show correlations of the sort predicted by the theory.

Known material of the subtribe Mekongianina is reviewed. The group comprises four little-known flightless, montane species from S.W. China and S.E. Tibet: Yunnanites coriacea and Mekongiana gregoryi, which are micropterous, and two apterous species, kingdoni and wardi, which are here transferred to a new genus, Mekongiella.

Agabus audeni Wallis, known only by the type from south-central British Columbia, is recorded from the eastern foothills of the Rocky Mountains just west of Calgary in southern Alberta. There are notes on its ecology and on its separation from other species, with a key to A. audeni and A. browni Leech. The Holarctic A. coxalis Sharp is discussed, and the Nearctic form referred for the first time to the subspecies ermaki (Zaitzev). Specific characters are illustrated.

Conophthorus lambertianae broods within cones in sunny places on the ground can be killed by high temperatures. This conclusion is supported by experimental evidence from four sources: (1) mortality of broods in cones placed in the sun; (2) mortality of cone beetles exposed to high temperatures in the laboratory; (3) measurements of internal cone temperatures occurring in nature; and (4) consideration of some factors that influence internal cone temperatures.

Pupae of the onion maggot, Hylemya antiqua (Meigen), did not complete their development when irradiated with 3.0 kiloroentgens within five days of pupal formation. Older pupae were not adversely affected. Females from treated pupae were sterile and laid no eggs when caged with normal males. The males from treated pupae were sterilized to a high degree, yet normal females mated with them and laid normal complements of eggs. Less than 0.2% of 10,616 eggs laid by normal females caged with sterile males hatched. A 6:1 ratio of sterile to normal flies reduced egg hatch to 1.7%.

Studies on the biology of Encarsia pergandiella Howard, a solitary, arrhenotokous endoparasite, revealed that fertilized eggs, which give rise to females, are deposited in whitefly nymphs preferably in second, third or fourth instar, while unfertilized eggs, which give rise to males, are deposited in Encarsia larvae at whose expense they develop. The parasite adults were observed to feed on body fluids of whitefly nymphs. Both sexes have a pupal and three larval stages, and development from egg to adult at approximately 75° F. takes 15 days for the females and 13 to 14 days for the males. Mean longevity of the females at constant and fluctuating temperatures was studied. Actual mean fecundity at 75 ± 4° F. was 48.5 eggs per female, all of which were deposited during the first 70% of her life, provided hosts were abundant. Field observations revealed that E. pergandiella was present throughout the year, reaching highest numbers in the spring and summer. The parasite does not have an obligatory period of dormancy for all of its individuals. E. pergandiella was not able to prevent whiteflies from causing heavy damage to plants. The reason may be in the discrepancy between the rate of increase of the whitefly and the parasite.

A leaf miner on ironwood, Chrysopeleia ostryaella Chambers, is recorded for the first time from Canada. Information on distribution, life history, habits, morphology of immature stages, and parasites is given.

Southwestern Manitoba, a semiarid area subject to periodic droughts, was originally covered by a mixed prairie on light sandy soil. Settlement commenced on the completion of the land survey in 1890. By 1913 all the land was taken up and a cereal grain economy had developed. Soil drifting became a problem and was particularly severe during the drought years of 1929 to 1934. Local species of grasshoppers, Melanoplus sanguinipes (Fabricius), Melanoplus bivittatus (Say) and Camnula pellucida (Scudder) first became pests during a minor drought in 1901 and occurred in a severe outbreak in the major drought period. Recently abandoned fields suffered severe wind erosion and drift ridges of soil provided the most favorable egg laying sites for M. sanguinipes and to a lesser extent for M. bivittatus. The effect of slope of ground on egg deposition and grasshopper behavior in relation to temperature and moisture are recorded. Succulent, introduced weeds and cereal crops supplied abundant food. C. pellucida, a grass feeder, was favored by the planting of cereal crops adjacent to egg bed sites among Carex stenophylla Wahl., and Agropyron smithii Rydb. on the roadsides. Methods of farming designed to prevent wind erosion, the use of herbicides and the grading of roadsides have shown the possibilities of ecological management to reduce grasshopper increase.

Two species of Tranosema (arenicola and taeniopus) are discussed from the standpoint of their nomenclature and taxonomy, and they are differentiated in a key. T. arenicola, the type-species of the genus, is redescribed and illustrated.