Abstract
The foxglove aphid, Aulacorthum solani, is holocyclic in Hokkaido, and overwinters in the egg stage. The total nymphal periods of oviparous female and male in the stage from the 1st to the 4th instar at 15°C were 12.5days and 24.5days, respectively. The average oviposition period of unmating oviparous females was 4.6days and these females survived for 23.5days after the first larviposition. Male adults survived for 25.8days at 12°C. In a field in the Tokachi district, the first oviparous female adults were recorded in mid-October and the first male adults somewhat later. It is considered that the time lag of adult appearance between oviparous female and male are due to the difference in their developmental periods.
