none This work describes population fluctuation, behavior and rate of parasitism in several stages of Lariocampidae which attack avocado leaves. Thirty trees were randomly searched every 15 days. for am year. Eggs, larvae and pupae were observed in the laboratory. Three species attacked leaves, Euglyphis rivulosa, Euglyphis fibra and Nesara drucei; they were most frequent between April and August of 1990 and April of 1991. E. rivulosa was abundant year round and was most attacked by parasitoids during development. Particularly, its eggs were parasitized by Telenomus sp. which was the most frequent end presented the highest percentage of occurrence. The larval stage of E. rivulosa was attacked by Microcharops anticarsiae, Apantales sp. and Charops sp., while the pupa had Brachymeria sp. and two other species of Tachiridae and Ichneumonidae. E. fibra was parasitized only by M. anticarsiae. This is the first mention of N. drucei snacking avocado leaves, and no parasites were associated with it.