Abstract
Experimental observations, made outdoors during the dry and wet seasons in Trinidad, demonstrate that more than 70% of female Aedes aegypti that are destined to oviposit within the next two hours enter ovitraps during the first and last two-hour periods in the day, a finding consistent with the diel pattern of oviposition recorded earlier at the same site. It is possible that proportionately more eggs are laid in the morning peak during the dry season than the wet season. Fewer eggs are laid within a two-hour experimental period if an open ovitrap is not accessible to females before the experimental period begins. It is inferred that, during the early afternoon, ovitraps are entered by females destined to lay eggs there more than two hours later in the same day.