The spring of 1945 was in general very unfavorable for the majority of Lepidoptera in the Ottawa area, due apparently to the killing frosts and wet weather of the latter half of April and throughout May, following abnormally high temperatures late in March and early April. However Coleophoridae were the exception to this condition and the cases of this group were much more abundant than usual. The continued cold, dry, winter weather, without any of the customary alternating thawing and freezing spells was seemingly very suitable to the hibernating larvae; the early warmth stirred them out of their winter lethargy fully a month sooner than usual and their cases proved a protection against the subsequent cold.