Adult schistosomes live in the bloodstream, and although the sexes are separate, males and females usually pair and exist in a semi-permanent state of copulation. The female lies within a groove in the body of the male, the gynecophoric canal. In this photo, the female is the narrower but darker individual that loops out of the gynecophoric canal in two places. The tails of the two individuals are visible at the lower right, but at the top the anterior end of the male only is visible. Females are about 20 mm long and 0.25 mm wide, while the male, at 15 mm long by 0.8 mm wide, is slightly shorter but considerably wider.