Key to species of Hamacreadium recognised here

1a. Genital pore distinctly extra-caecal........................................................................ 2

1b. Genital pore caecal or inter-caecal, not extra-caecal...........................................................3

2a. Vitelline follicles confluent in forebody, distinctly interrupted about ventral sucker, extend anteriorly at least to the intestinal bifurcation; cirrus-sac cylindrical...................................................... H. interruptum (Fig. 3 a)

2b. Vitelline follicles not confluent in forebody, not interrupted, distinctly post-bifurcal; cirrus-sac clavate, sigmoid.................................................................................................. H. lutiani (Fig. 4 b)

3a. Anterior extent of vitelline follicles distinctly pre-bifurcal.....................................................4

3b. Anterior extent of vitelline follicles bifurcal or post-bifurcal....................................................5

4a. Vitelline follicles extend to anterior margin of pharynx...................................... H. phyllorchis (Fig. 5 b)

4b. Vitelline follicles terminate posterior to pharynx.............................................. H. mutabile (Fig. 1)

5a. Anterior extent of excretory vesicle pre-bifurcal........................................ H. longivesiculum (Fig. 4 a)

5b. Anterior extent of excretory vesicle distinctly post-bifurcal.....................................................6

6a. Anterior extent of vitelline follicles post-bifurcal.............................................. H. lethrini (Fig. 3 b)

6b. Anterior extent of vitelline follicles bifurcal................................................................ 7

7a. Cirrus-sac sigmoid, extends dorsal to posterior half of ventral sucker............................... H. cribbi (Fig. 2 a)

7b. Cirrus-sac straight to curved, entirely anterior to ventral sucker or extending dorsal to anterior half of ventral sucker.......8

8a. Ovary four-lobed...................................................................... H. morgani (Fig. 5 a)

8b. Ovary many-lobed................................................................... H. hainanense (Fig. 2 b)