Field populations ofHaplaxius crudus(Van Duzee) were studied on St. Augustinegrass,Stenotaphrum secundatum(Walt.) Kunze; bahiagrass,Paspalum notatumFlugge; and bermudagrass,Cynodon dactylon(L.) Pers. andC. X magenissiiHurcombe, from July, 1974, to July, 1975, in Ft. Lauderdale, Florida.Haplaxius cruduscompleted development on all 3 species of grasses. Significantly higher numbers (P<0.01) of adults and nymphs were collected on St. Augustinegrass; however, populations fluctuated less throughout the year on bahiagrass.H. crudushad a sex ratio of 1.7♀:1♂ in this study. The sex ratio was biased toward males during the population peaks of adults.