C. formosa may refer to:
Callipero formosa, a longhorn beetle Callista formosa, the floral emblem of Ranong Province, Thailand Calocitta formosa, a Central American jay Canna formosa, a garden plant Carcelia formosa, a tachina fly Cephalopholis formosa, a Pacific grouper Chacodelphys formosa, a didelphimorph marsupial Chloromyia formosa, a soldier fly Chrysanympha formosa, a North American moth Cirrimaxilla formosa, a saltwater eel Clavus formosa, a sea snail Coris formosa, a wrasse native to the Indian Ocean Cosmopterix formosa, a cosmet moth Crematogaster formosa, a cocktail ant Cuspivolva formosa, a sea snail Cyprinella formosa, a ray-finned fish