Another group of trematodes found in the small intestine of cats is the Diplostomatids; adult diplostomatids occur in the intestine of birds and mammals. These trematodes are similar to the cyathocotylids in that they possess a tribocytic organ. However, they are typically divided into a marked forebody and hindbody. Cyathocotylids also possess an organ called the cirrus sac that is absent in the diplostomatids.

Four species of Diplostomatid have been reported in cats. One of these species, Alariamarcianae, has been shown capable of infecting young cats through the milk of queens that contain larval stages in their tissues.