During July 1985 to June 1986, we surveyed the arthropod fauna associated withPistia stratiotesL., waterlettuce, in Florida. Plant samples were collected at 61 sites. Samples comprised a minimum of 20 waterlettuce rosettes. Invertebrates were removed from the plant sample using a submergence technique. Eighteen phytophagous species were recovered fromP. stratiotes. Six of these species are known waterlettuce feeders. They include the mothsPetrophila drumalis(Dyar),Synclita obliteralis(Walker), andSamea multiplicalisGuenée, the aphidRhopalosiphum nymphaeaeL., the leafhopperDraeculacephala inscriptaVan Duzee, and the weevilTanysphyrus lemnae(F.). Most of these insects are either stenophagous or polyphagous; none feed exclusively on waterlettuce. The paucity of specialists on waterlettuce in Florida contrasts sharply with the richness of oligophagous species in South America. This suggests that water lettuce is not a native species, despite observations of its occurrence in Florida as early as the mid-1700s.