hh. Mandibles in the male chelate ([fig. 158 j]), in the female long, styliform. Parasitic on birds. Dermanyssus Dug.
Two species of importance may be noted, D. hirundinus and D. gallinæ. The latter ([fig. 51]) is a serious pest of poultry, sometimes attacking man, causing itching and soreness.
ee. Anal plate absent. In lungs and air passages of some mammals. Halarachninæ.
dd. Free or attached to insects, rarely on vertebrates.
e. First pair of legs inserted within the same body opening as the oral tube; genital apertures surrounded by the sternum. On insects. Uropodidæ.
ee. First pair of legs inserted at one side of the mouth opening; male genital aperture usually on the anterior margin of the sternal plate. Gamasidæ.
This family contains a number of genera, some of which are found upon mammals, though the majority affect only other arthropods. One species, Lælaps stabularis, frequents the bedding in stables, and in one instance at least, has occasioned irritation and itching, in man.
bb. No distinct spiracle in the stigmal plate on each side of the body.
c. Body usually coriaceous, with few hairs, with a specialized seta arising from a pore near each posterior corner of the cephalothorax; no eyes; mouth parts and palpi very small; ventral openings of the abdomen large; tarsi without sucker. Not parasitic. ORIBATOIDEA.
cc. Body softer; without such specialized seta.