The biology and early stages of Eccopsis galapagana Razowski & Landry are described and illustrated for the first time; details of the adult behavior also are provided. Under outbreak conditions the species has become a serious pest in silvopastoral systems of algarrobo tree (Prosopis juliflora (Sw.) DC.; Fabaceae) in Colombia. Although African members of the genus Eccopsis feed on a variety of different host plant families (e.g., Fabaceae, Rhizophoraceae, Sterculiaceae, Anacardiaceae, Euphorbiaceae, Flagellariaceae, and Rutaceae), New World species of Eccopsis are recorded only from Fabaceae.