The Effect of Mercury Vapour on the Eggs of Calandra granaria (L.) (Col., Curculionidae)

Abstract

1. To determine the percentage hatch of Calandra granaria eggs, the grain containing them should be kept for 6–10 days at 25°C. after a two-day oviposition period.2. Pretreatment of grain with mercury vapour makes no difference to the fertility of eggs afterwards laid in it.3. At 25°C. 99 per cent. of the eggs are sterilised in 24 hours and 87 per cent. in 8 hours, using what probably approaches the saturated vapour.4. At 10°C., the sterilisation for periods of 24, 48, and 72 hours is 44, 87 and 93 per cent. respectively.5. At 25°C., mercury vapour will penetrate at least 30 cm. of grain in 2 days. At 12°C., mercury vapour will penetrate at least 90 cm. of grain in 7 days.