. Annual report. Entomological Society of Ontario; Insect pests; Insects. ENTOMOLOGICAL SOCIETY 49 Table 2 tabulates the results for Lepidoptera emerging in the spring, all of which are to be found feeding upon the foliage of spruce. In general, it may be observed that, as is nicely shown in the sawflies, the larger the species the greater the amount of effective heat required to produce emer- gence. There are two notable exceptions here, namely the small Carvpeta, which has a delayed emergence, and the large Feralia, which when it emerges at all does so early. This table strikingly shows that
. Annual report. Entomological Society of Ontario; Insect pests; Insects. ENTOMOLOGICAL SOCIETY 49 Table 2 tabulates the results for Lepidoptera emerging in the spring, all of which are to be found feeding upon the foliage of spruce. In general, it may be observed that, as is nicely shown in the sawflies, the larger the species the greater the amount of effective heat required to produce emer- gence. There are two notable exceptions here, namely the small Carvpeta, which has a delayed emergence, and the large Feralia, which when it emerges at all does so early. This table strikingly shows that the very com- mon green spruce looper (Semiothisa granitata) is host to numerous par- asites representing a great diversity of species. The outstanding features of the 1938 survey may now be considered. The summer in Eastern Canada was characterized by temperatures above normal throughout, and by excessive rainfall in all months except June. The decrease in the population density of the European spruce sawfly {.Diprion polytomum Htg.) in the infested areas of Quebec north of the St. Lawrence and in Ontario may perhaps be attributed largely to climatic factors (Fig. 1). Moreover, promising results have attended the libera- tions of Microplectron fuscipennis Zett., the percentage parasitism by this species alone averaging as high as per cent, for all the area south of the St. Lawrence (summer emergence from 1938 cocoon samples).. Fig. 1.—Degree of Infestation of European Spruce Sawfly in 1938. The reports received in 1938 suggest that the boundary of moderate infestation has apparently receded on the north shore, and in northern Quebec there is a recession even in the distribution outline. However, an important new area of moderate infestation has been discovered in south- ern Ontario. Population densities south of the St. Lawrence are derived from quantitative larval and cocoon samples analysed by the Fredericton Please note that these images are extracted f
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectinsects, bookyear1872
