The male fluke is holding the female, and the front end of the female fluke (indicated with a yellow arrow) is protruding from the male. Red dashed lines show high magnification images of the outer surface, or tegument, of a healthy male fluke (top right) and a damaged male fluke (bottom right). Collins et al. revealed that stem cells called neoblasts provide the new cells needed to repair the tegument when it is damaged. Images courtesy of L. Becker, P. Wangchuk, J. Whan, M. Pearson and A. Loukas.