Abstract
Mosquitoes were collected in the dwellings at Tomatsuri from June to September in 1948, at Wakakusa from July to September in the same year, and at Kanuma from July to October in 1951. 1) Mosquitoes of four genera and six species were observed in these three places. The species of mosquitoes found in each places. The species of mosquitoes found in each place was almost similar to one another. These mosquitoes were constituted from an overwhelmingly great number of Culex pipiens and a small number of Anopheles sinensis, Culex tritaeniorhynchus and Culex bitaeniorhynchus. 2) The most important species that commanded the seasonal occurrence of mosquitoes in the dwellings was C. pipiens. This species appeared in small numbers in the middle of June and reached the highest population in the middle of July. Then, they decreased gradually in number and became still fewer in August and September. After October they could not be found at all.
