Outdoor resting of Culex pipiens fatigans in Rangoon, Burma.

The sites occupied by resting adult mosquitos are of importance, since they may be accessible to treatment with insecticide. It has usually been assumed that Culex pipiens fatigans feeds and rests indoors, thus making itself vulnerable to indoor spraying. However, work in the Kemmendine Experimental Area of Rangoon, Burma, has now shown that many C. p. fatigans rest out of doors in a variety of shelters. The lower parous rate in outside catches as compared with indoor catches tends to confirm the view that newly hatched C. p. fatigans rest out of doors for some time before setting off to feed. The percentage of infected mosquitos is remarkably constant from site to site and from month to month and does not differ significantly from that obtained in indoor resting catches or on bait out of doors. It appears that the possibility of acquiring infection out of doors will have to be seriously considered in any anti-filariasis campaign.