. The Canadian field-naturalist. Figure \. Sex and age composition of spiders in each habitat. constant throughout the sampling period, the male spider catch decreased noticeably after mid June (Figure 2), similar to Hauge (1977). Mid July was a peak period for the number of immatures (Figure 3). The population peak occurred in mid June for the male population as well as the total adult population. These results indicate that had the sampling period been extended to include May and September a den- sity trend similar to that reported by Peck (1966) and MacMahon and Trigg (1972) would have occu
. The Canadian field-naturalist. Figure \. Sex and age composition of spiders in each habitat. constant throughout the sampling period, the male spider catch decreased noticeably after mid June (Figure 2), similar to Hauge (1977). Mid July was a peak period for the number of immatures (Figure 3). The population peak occurred in mid June for the male population as well as the total adult population. These results indicate that had the sampling period been extended to include May and September a den- sity trend similar to that reported by Peck (1966) and MacMahon and Trigg (1972) would have occurred. They suggest density peaks during early (mid May-24 June) and late (4 August-12 September) summer and a density depression in midsummer (25 June-3 August). Annotated List Theridiidae Robertus sp. imm. Robertus riparius Keyserling. Central and eastern North America. Very common in wooded areas. Theridion sp. imm. Theridion aurantium Emerton. Mainly New Eng- land and Great Lakes area and adjoining areas in Canada; Newfoundland. Adult ——— Immature. July Sample Period August 13 18 23 28 3 8 13 18 23 28 2 7 12 June July Sample Period August Figure 2. Number of adult male and female spiders caught during the sample period, 13 June - 16 August 1971. Figure 3. Total number of adult and immature spiders caught during the sample period, 13 June - 16 August Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Ottawa Field-Naturalists' Club. Ottawa, Ottawa Field-Naturalists' Club
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