It has not been possible to confirm the statement that DDT brings about increased egg production in the European red mite, Panonychus ulmi (Koch). Newly emerged females were allowed to oviposit individually on single, whole, isolated apple leaves for their entire lifetime. On leaves sprayed with DDT, with mean deposits of 3.1 and 10.6 μg per sq. cm, the total egg production per female, the length of life, and the daily rate of oviposition were not significantly different from those on nonsprayed leaves. Females were also placed on isolated leaves, one-half of which had been sprayed with DDT. These females subsequently spent 3.4 times as much time on the unsprayed halves of the leaves as on the sprayed halves; they laid 5.6 times more eggs on the former than on the latter. This species, therefore, is evidently irritated and repelled by DDT.