Öz The response of the larvae and pupae of Aedes aegypti (L.) Anopheles stephensi Liston and Culex pipiens L. to surface disturbance, for which a surface ripple was produ- ced by water drops of peristaltic pump was studied. Ouaütative and quantitative es- timates and ontogenic aspects of the response ,were considered. AH the species studied here,in general, showed a diving down response to this stimulus, but a small number of Anopheles stephensi showed a sidetvays run. In the three species, the response changed vvith the age; it gradually decreased in A. aegypti and C. pipiens but increased in A. stephensi.