Great southern white
This butterfly is common in coastal areas where its lazy, low flight may visit a garden near you. During population outbreaks in southern Florida, thousands of these white butterflies can be observed flying northward along the coast.
Great southern white Ascia monuste phileta (Fabricius) (Family: Pieridae)
Florida range: Throughout the state along the coast; inland in central and southern Florida
Larval host plants: Wild Mustards (Brassica species); Pepper Grass (Lepidium virginicum); Saltwort (Batis maritima); Sea Rocket (Cakile lanceolata)
Flight: All year in south Florida, summer months in northern part of state
Occurrence: Common
Link for more information: http://www.npwrc.usgs.gov/resource/distr/lepid/bflyusa/usa/765.htm