Larval development of the caryophyllaeid cestode Glaridacris confusa occurs in aquatic annelids of the families Tubificidae and Naididae. Procercoids possess a cercomer; the scolex and gonads are well developed. North American caryophyllaeid cestodes parasitize catostomid and cyprinid fishes; oligochaete annelids serve as their intermediate hosts. Glaridacris confusa Hunter is one of the five species currently assigned to the genus Glaridacris Cooper. Yamaguti (1959) correctly listed this species as G. confusa (not the G. confusus of Hunter, 1929) since the generic name is feminine. G. confusa has been recorded from Ictiobus bubalus Raf. and Ictiobus sp. from the Rock River, Illinois and the Mississippi River, Iowa (Hunter, 1929); from Carpiodes carpio (Raf.), Lake Texoma, Oklahoma (Self and Timmons, 1955); and from I. bubalus, I. cyprinellus (Val.) and I. niger Raf., Lake Texoma (Self and Campbell, 1956). This is the first account on the life cycle of G. confusa. Experiments conducted with G. catostomi Cooper and G. oligorchis Haderlie showed that oligochaetes of the genera Limnodrilus and Tubifex serve as intermediate hosts (McCrae, 1961; Calentine and Fredrickson,