Genus of Itara Walker, 1869 (Orthoptera: Gryllidae) includes 10 subgenera and 54 species worldwide. These species are mainly distributed in the Asia-tropical region (e.g., Malay Archipelago, India, Vietnam, and Thailand). In China, one species (Itara minor Chopard, 1925) has long been identified from tropical regions. In this study, three subgenera and eight species of Itara have been identified. Three new species are described (Itara (Itara) basidentatanew species, Itara (Itara) dicrananew species, and Itara (Gryllitara) denudatanew species, and four new distribution records are reported. Descriptions and illustrations for eight species are provided.

The Arthrogastra of North America have scarcely been studied except in two or three families, the principal part of the American literature consisting of scattered notes and descriptions. Two or three more pretentious papers have been published by Wood, Putnam and Hagen. A broad field for study is open for future investigators. In order to call attention to the group and secure such co-operation of collectors as may be possible, the following preliminary list of twenty genera and fifty-nine species has been prepared. A few forms are added from Lower California and Cuba which will probably be found within the limits of the United States. Additions and corrections to the list are solicited, as well as specimens from all parts of the country, for which a suitable return will be made.

This species conforms very well with the generic diagnosis given in my previous paper, except in having the thoracic and abdominal sculpture greatly reduced. In the key to species it traces to ungavae Wly., but differs from that species, as well as from all others included in the key, in having the antennae unusually short, with the flagellar segments fewer in number and considerably stouter than in any of these species. In addition, in phygadeuontoides the thorax is notably elongate, with the mesoscutum strongly flattened, and the legs, especially the femora, are unusually short and stout; these characteristics, in conjunction with the generally black body color, being suggestive of some of the smaller Phygadeuonini.

Nomada Granicheri, n. sp.—♀. Length, about 10½ mm.; black, with bright lemon-yellow markings, the only red is on base fo antennæ, legs, and a little on mandibles; mandibles simple; anterior coxæ without spines; basal nervure meeting transverso-medial; third antennal joint slightly longer than fourth. This is a Xanthidium with the face black in the middle and with yellow lateral marks, like teh European N. succincta.

well over half the agricultural weeds in Canada are introduced species, many of them introduced without their chief insect enemies. Biological control, by the introdtiction of these insects, would reduce the aggressiveness of these weeds; but it should be regarded as a supplement to, and not a replacement for, mechanical or chemical control as it is most likely to succeed where these methods are ineffective or impractical. Thus the weeds chosen for biological control are either: resistant to chemical or mechanical control; serious pests of range or other low quality land where conventional methods of control are impractical; or resistant to control because they are continually spreading on to arable land from hedgerows and waste areas.

The genus Syndyas Loew is revised for North America, and four of the six included species are described as new. A general description of the Nearctic species group is given, and keys are presented. All species but one are restricted to eastern North America. Three unplaced specimens that may represent additional species are discussed.

In a paper published during the war Reeks pointed out that the sawfly which has caused much damage in the forests of Canada for about twenty years is identical with Lophyrus hercyniae, described by Hartig in 1837. In the same work he proved that Hartig was correct in describing hercyniae as a species distinct from Lophyrus polytomus Htg. Enslin's view that the two species should be united under the name polytomus is quite wrong. Reeks has shown that important biological and anatomical differences exist between them. Benson erected the genus Gilpinia for the species polytomus and for allied species. Reeks was unable to examine the types of the two species, kept in the Hartig collection in Germany, and for that reason he sent to me some specimens of the “European spruce sawfly” from Canada, with the request that I compare them with the types in the Hartig collection. The results of my examination are as follows.

The Canadian program in insect pathology is reviewed in general terms. The pathogens that have been studied include viruses, fungi, bacteria, protozoans and nematodes. Many aspects of the various host-parasite relationships have been investigated under field and laboratory conditions.

Allied to basicornis Kngt., but easily distinguished by the much larger size, shorter rostrum which only attains posterior margin of sternum, and by the fuscous markings of the male.

From the heart of the Sierras, in California, comes a new mosquito of the genus Taeniorhynchus, which is here described:

Taeniorhynchus Sierrensis, n. sp.—æ. Head brown, a median line of white curved scales extending up between the eyes, immediately followed laterally by a patch of flat brown scales, a narrow white stripe laterad, followed by a brown stripe, narrow white line around the eyes, white forked and curved scales on the occiput; the general effect is of two brown submedian spots, and the curved scales are confined to this comparatively narrow median line; antennæ brown, and white not really banded, giving the effects of white bands, verticels brown, pubescence white, basal joint white scaled; palpi brown with white tips, and a narrow light band about midway; proboscis dark brown, clypeus brown, eyes brown.

Many aphid species (Hemiptera: Aphididae) that feed on herbaceous crops exhibit a rise and then sudden decline in abundance. Data from a nine-year study of Uroleucon rudbeckiae (Fitch) on Rudbeckia laciniata Linnaeus (Asteraceae) are used to investigate this pattern of seasonal abundance in a non-agricultural aphid. Aphids on a population of tagged and numbered flower stems were counted weekly. Abundance (mean aphids per stem) was partitioned into prevalence (proportion of stems colonised) and mean intensity (aphids per colonised stem), and also considered as the sum of the aphids in individual colonies. Abundance rose in mid-summer to late summer and then declined, peaking between the end of July and mid-September, earlier in years when the peak was higher. Prevalence showed a more uniform and consistent peak than mean intensity. Most of the 949 colonies were small and short-lived, but a small proportion were long-lived and reached 1000 aphids. Large colonies declined more slowly than moderately-sized colonies. Severe weather, shortening day-length, decline in host quality, density-dependent effects on rate of increase, and emigration failed to explain the population decline. An early rise and later decline in immigration, in conjunction with increasing predation through the summer, were consistent with the decline.

The radiosensitivity of Prostephanus truncatus (Horn) and Tribolium castaneum (Herbst) to 60Co radiation was determined at doses of 5 to 100 krad. P. truncatus was more radiosensitive than T. castaneum at 5, 15, and 25 krad (P < 0.05) at 8 and 16 days after irradiation but after 24 days all individuals irradiated at 15 and 25 krad were dead. At 50 or 100 krad all individuals of both species died in 16 or 12 days, respectively. Dose rates of 1.07 to 12.84 krad/min for a total delivered dose of 25 krad had no effect on the speed of lethal response. The results indicate that on economic grounds alone, it may not be justified to use 50 or 100 krad to accelerate the onset of death by 8 or 12 days, respectively.

Larvae of three species of Proteoteras (P. willingana (Kearfott), P. crescentana Kearfott, and P. aesculana Riley) attack shoots of Manitoba maple (Acer negundo L.) in the Canadian prairies. Larvae of P. willingana and P. crescentana have been confused because both cause gall formations on Manitoba maple and both lack the anal fork that is present in P. aesculana. This paper describes the ultimate larval instar and pupa of P. crescentana. Keys are presented to separate mature larvae, pupae, and adults of the three species.

During development, many chromatophores on the air sacs of larvae of Chaoborus Lichtenstein disperse to the tracheal trunks and throughout the body of the pupae. In male pupae, chromatophores on the posterior air sacs move to the developing testes and vasa deferentia and some become the adventitious spotting previously reported for adults of Chaoborus. In larvae of Mochlonyx Loew, chromatophores have a similar development pattern, but in female pupae some also surround the spermathecae. Larvae of Eucorethra Underwood have chromatophores scattered throughout much of the body but it is uncertain whether these are homologous to those of Chaoborus and Mochlonyx. Outgroup comparisons show that the migration of chromatophores from the larval air sacs to the adult male testes and vasa deferentia is a synapomorphy of Chaoborinae. The presence of pigmented fat body on the larval testes in many Culicidae, Eucorethra, and Mochlonyx is plesiomorphic, and the transparent larval testes in Chaoborus are a synapomorphy of the genus. The dark adult testes in Mochlonyx are derived from pigmented larval fat body and chromatophores from the larval air sacs, and this is proposed as an intermediate evolutionary state. It is likely that the chromatophores surrounding the testes of pupae of Chaoborinae provide protection against ultraviolet radiation, but further study is needed.

Gynaephora groenlandica (Wocke) (Lepidoptera: Erebidae) is a cold-adapted species, whose life history traits are dictated by cold and short Arctic summers. We used a recently discovered alpine tundra population in southwestern Yukon, Canada to investigate local adaptations to habitats with different environmental conditions (alpine versus Arctic). Using cafeteria-type experiments and field observations we examined the diet breadth of alpine populations of G. groenlandica beringiana Schmidt and Cannings, and compared these to published data on High Arctic populations of G. groenlandica groenlandica and to the closely related G. rossii Curtis. Gynaephora groenlandica beringiana appears to have a broader diet than High Arctic populations, but similar to that exhibited by alpine populations of G. rossii. Such trends could emerge from reduced synchrony between herbivores and their host plants in less extreme environments, and possibly from a reduced incidence of parasitoids in the life cycle of these populations. Our findings indicate the larval host plant plasticity of G. groenlandica in different environments, and are relevant to predictions regarding the fate of these populations under climate warming scenarios.