Precipitation and A. aegypti eggs densities in the neighborhood of Engenho do Meio, Recife, Pernambuco. Data are from November 2008 to March 2009. A, B, C and D represent groups of 12 or 13 ovitraps differing from each other only by trap installation period (first, second, third or fourth week). Each group was assessed in four cycles of 28 days. Line represents rainfall (mm) in the period. Bars are standard errors.