Molting of T. spiralis IIL larvae at different time points post-infection. Larval molting was observed at various times post-infection by microscopy. The larvae carrying a sheath at the posterior end were counted as molting worms. A, B, C, G, I, K: IIL without molting. D, E, F, H, J, L: IIL encased in cuticle (arrow). Copulatory appendage is indicated with a triangle.