Hymenolepis nana, or the dwarf tapeworm (only 40 mm long!), is thought to be the most common human cestode on the planet. Unusual amongst tapeworms, H. nana does not require an intermediate host, but can be passed simply from one person (or rodent) to another via the ingestion of eggs that are shed in the feces, and auto-infection occurs in parts of the world where the worms are common. This direct life cycle is thought to be a recent adaptation in this species as the life cycle can be completed via an intermediate such as a flour beetle, much like its cousin, H. microstoma that you met way in the beginning of the year.
Image from the CDC Public Health Image Library.