Life Cycle: “Haematoloechus longiplexus has a complex 3-host life cycle with freshwater pulmonate planorbid snails, e.g., Physa gyrina, as the first intermediate hosts, odonates (dragonflies and damselflies) as the second intermediate hosts, and frogs as the definitive hosts” (Novak and Goater, 2013).
"Body elongate, 4.90-8.64 (5.86) mm long by 1.50-2.27 (1.77) mm wide. Tegument spined or not. Oral sucker terminal, 0.286-0.469 (0.380) mm long by 0.330-0.5 12 (0.149) mm wide. Acetabulum medial, slightly posterior of ovary, 0.18-0.260 (0.197) mm wide. Pharynx muscular, 0.165-0.336 (0.243) mm long by 0.154-0.276 (0.26) mm wide. Intestinal caeca narrow tubes, extending to near posterior extremity. Testes parallel, elongate, lobed or not. Ovary lobed or not, anterior to acetabulum, pretesticular. Extracaecal uterine loops present, extending anterior beyond the ovary, often extending to the level of the pharynx. Genital pore ventral to pharynx. Vitellaria follicular, symmetrically placed on each side of the body. Extent ranging from about level of intestinal bifurcation, and terminating posterior to the testes. Eggs operculate, 0.022-0.025 (0.023)mm long by 0.015-0.018 (0.016) mm wide.
Sources: Kennedy, M.J. 1981 A revision of species of the genus Haematoloechus Looss, 1899 (Trematoda: Haematoloechidae) from Canada and the United States. Canadian Journal of Zoology, Vol. 59, p. 1836–1846.
Novak, C.W. and Goater, T.M. 2013. Introduced Bullfrogs and Their Parasites: Haematoloechus longiplexus (Trematoda) Exploits Diverse Damselfly Intermediate Hosts on Vancouver Island. Journal of Parasitology, Vol. 99, No. 1, p. 59-63.