Cloudless sulphur
Phoebis sennae
Large lemon-yellow butterfly whose larvae feed on legumes in the genera Senna, Cassia, and Chamaecrista (Fabaceae); the caterpillars sequester compounds from these hosts as a chemical defense. Adults have an exceptionally long proboscis and favor deep, often red or pink tubular flowers that shorter-tongued visitors cannot reach. A strong flier, the species mounts large seasonal emigrations northward each summer and retreats south to overwinter, making it a familiar late-season garden visitor well beyond its core breeding range.
Conservation
Common and secure across its range with no IUCN, Xerces Red List, or USFWS listing; the USDA Forest Service describes its populations as abundant and thriving. Habitat loss along migratory corridors is the noted long-term pressure on this and other migrating butterflies.