Spatial distribution of mosquitoes around a bovine host was studied in November 1997 lnnorthern Thailand (17"38'N, 99"23'E). Forty bamboo stakes were arranged I m apart, in 4 rays of 10, around acow tethered in an open field. AII mosquitoes found resting on the stakes were collected by aspiration between7:00 p.m. and 11:00 p.m., sexed, and identified to species; and f'eeding status was categorized as fed or unfed.Collections were repeated over 8 nights, with and without the host cow. A total of 1,566 mosquitoes from 25species (5 genera) was collected. Anopheles aconitus was the most abundant species (643 individuals), followedby An. peditaeniatus, Culex vishnui, and Cx. pseudovishnui. We found that the number of mosquitoes collectedfrom the stakes was related to the presence of the cow host; the number of mosquitoes collected was unrelatedto the compass point location of the bamboo stakes, with the exception of Mansonia uniformis; unfed mosquitoespreferred bamboo-stake resting sites that were closer to the host; the daily fed to unfed ratio of the dominantspecies was negatively correlated with the daily total number of mosquitoes collected; and fed and unfed mosquitoesclustered in interspecific heterogeneous groups around the host cow. Cluster analysis separated the speciesinto 2 groups. The 1st consisted of 5 species with higher proportions of fed mosquitoes, whereas the 2nd,represented by 7 species, aggregated around the host within a distance of 1-4 m with lower proportions of fedmosquitoes. The interspecific variation in the distribution of unfed females was presumed to be due to a lackof feeding success. We discuss the significance of prebiting resting. In cases in which large numbers of mosquitoesare present, prebiting resting can be adaptive to avoid host defensive behavior triggered by attackingmosquitoes.