Family Haaseidae Attems, 1899

Diagnosis: Small to medium sized craspedosomatideans, up to 12 mm. Body with 28 or 30 segments, including telson. Body segments with dorsolateral humps bearing stout, long and trichoid macrochaetae. Males: Leg-pairs 3–7 with tarsal papillae in distal half; leg-pair 10 modified, with coxal sacks and a robust coxal process; leg-pair 11 with coxal sacks and no other modification.Anterior gonopods with well-developed medial sternal process; angiocoxites erected, apically with trichoid cuticular outgrowths, supplied with several additional processes; (?) seminal canal easily visible. Posterior gonopods with robust telopodites, and mesal coxal processes, sternum reduced. Females: Sternite of the third pair of legs with lateral lobes (in H. nontronensis telopodites are reduced to one podomere only). Vulvae with membranous operculum; bursae merged at least posteriorly with mesal and lateral parts, bearing long setae and small triangular denticles. Postgenital plate present at least in some Hylebainosoma and Haasea species.