Egg laying behavior in Aedes triseriatus was studied in an oak woodlot endemic for La Crosse encephalitis virus in southwestern Wisconsin. Daily counts from oviposition traps allowed the calculation of spatial distribution parameters for eggs during 1988. Egg distribution along an ellipsoidal transect of 25 traps was clumped with some traps being more attractive to ovipositing female Ae. triseriatus than others. Females were estimated to deposit a mean of 31 +/- 9.8 eggs per oviposition.