Haemadipsidae are a family of "jawed leeches". The latter might be (but probably are not) a natural, monophyletic group of hirudiniform proboscisless leeches. The scientific names mean "blood-drinkers". These leeches have five pairs of eyes, with the last two separated by two syeless segments. Most have two jaws, but some have three. The family is monotypic, containing only the subfamily Haemadipsinae, though as the family can apparently be divided into two or three distinct lineages, at least one of the proposed splits, while not a distinct familiy, might be a valid subfamily.
Commonly known as jawed land leeches, these annelids are known from subtropical and tropical regions aroud the Indian and Pacific Ocean. Well-known Haemadipsidae are for example the Indian Leech (Haemadipsa sylvestris) and the yamabiru or Japanese Mountain Leech (Haemadipsa zeylanica). Members of the family feed on blood, except Idiobdella which has adapted to eat small snails.
The other notable group of jawed blood-sucking leeches are the aquatic Hirudinidae. The Xerobdellidae are sometimes included in the Haemadipsidae, but their status as a distinct family is supported by sequence analysis of the nuclear 18S and 28S rDNA and mitochondrial COI genes as well as the anatomy of their sexual organs and nephridia; the latter are located at the belly rather than along the body sides as in the Haemadipsidae proper. All Xerobdellidae have three jaws.
Haemadipsidae probably originate in the Triassic, mnorte than 150 million years ago (mya). The diversification of the large Asian genus Haemadipsa probably did not take place until the Eocene, about 50 mya.