Diel oviposition patterns of Anopheles homunculus were determined from field-collected females in Platanal Forest, Cumaca, Trinidad. The timing and number of eggs oviposited were monitored at 2-h intervals for a set of 30 individual females and a group of 130 females. Individual females of An. homunculus displayed a strongly nocturnal pattern of oviposition. During the 1st gonotrophic cycle, > 65% of ovipositions occurred and > 70% of eggs were laid between 2200 and 0200 h. In the 2nd gonotrophic cycle, 79% of eggs were laid during the same time period. The same trend was found for the 130 females caged together, with > 80% of eggs laid between 2200 and 2400 h. The length of the gonotrophic cycle ranged from 74 to 102 h (mean 81.8 +/- 11.9 h) for the 1st gonotrophic cycle and from 46 to 76 h (mean 56.0 +/- 12.6 h) for the 2nd cycle. The fecundity of An. homunculus averaged 62 eggs in each gonotrophic cycle. No females survived in the laboratory longer than 10 days. These observations on An. homunculus oviposition patterns are the 1st for any species in the subgenus Kerteszia and may be useful for future attempts at colonization.