Arhynchobdellida Rhynchobdellida Euhirudinea, the true leeches, are an infraclass of the Hirudinea.

It may be that the presumed sister taxon of the Euhirudinea, the Acanthobdellidea, turns out to be more distantly related, as was already the case with the Branchiobdellida.

Euhirudinea leeches tend to hunt for nutrients in the morning or afternoon.

Therefore, feeding in the morning seems to be more nutritious for the leeches than in the afternoon.

Terrestrial Euhirudinea leeches, which inhabit tropical or subtropical environments have been found a greater number on-trails compared to off-trail numbers.