Abstract
In Triatoma phyllosoma, T. infestans and Panstrongylus megistus egg laying in LD 12:12 occurs during the dark phase of the light cycle with a marked peak near the light off signal. The timing of maximum oviposition is influenced by the ratio of light to darkness. The rhythm of oviposition is circadian, free‐running in DD in P. megistus and in LD 2:22 in T. infestans and T. phyllosoma.