(Mosquito life in drying pools.)
Experiments with larvae and pupae of C. pervigilans showed that they were able to survive for over a week in merely damp conditions, such as the mud of pools or damp vegetable debris. Under
such conditions the pupae changed to adults in two hours instead of the normal two or three days and practically all the larvae in the last instar (i.e. 4th) at once pupated and were ready for the final change before the pool became dry. Larvae in the earlier stages (1st and 2nd) would, however, be unable to pupate and would perish when the damp material became dry. In another test, with the larvae in mud at 62–64° F., 20 per cent, survived three days' drying; at 72° F. all died in three days.
From the point of view of control measures these observations indicate the necessity of clearing, as well as draining, pools and blocked water-courses.