Abstract.-Only twospecies, Xystrologa grenadella (Walsingham)and X. nigrovitta (Walsingham),ofthe predominantly Neotropical genus Xystrologa are known to occur in theW est Indies. Xystrologa antipathetica (Forbes), originally described from Puerto Rico butalso reported from the United States (Florida), is considered ajunior synonym of X. grenadella.The adults of both species andthe larvaand pupa of X. grenadella are describeda nd illustrated. The larval habits of theg enus are reported fort he first time as ag eneral detritovore, feeding on woody refuse, the bark of Ficus trees (in Florida, USA), fungi, andthe roots of orchids, andpineapple (in Puerto Rico). The injury that larvae of X. grenadella can inflict upon cultivated orchids in Florida is summarized. The introduction of X. grenadella is reported for the first time in the Old World, asapest of greenhouse plants in Germany.