Larvae of both Aedes triseriatus (Say) and Aedes atropalpus (Coquillett) produce oviposition attractants active for A. triseriatus, even when the larvae are pretreated with kaolin. These experiments demonstrate that the earlier observed attractancy of larval holding waters was not simply due to the presence of waste matter or associated microorganisms from the larval gut. It is further shown that the active material may be extracted directly from the larvae into hexane or ether. It is also demonstrated that the larval produced oviposition attractants of these species are similar in their ability to attract gravid females of A. triseriatus.