Distributional loci forCeratitis capitata(Wiedemann) were mapped for all major islands in Hawaii. Generally, loci were located in or near leeward dry areas at both high and low elevations. Fruit utilization varied by locality as well as by host species. Host fruit utilization byC. capitataexceeded that ofDacus dorsalisHendel in certain areas; in others, the situation was reversed. In some areas these two species appeared to coexist in apparent harmony; in others,C. capitatawas displaced by D.dorsalis.