jj. Porose areas elongate, shield brown, in the female with an apical silvery mark, in the male with two small and two or four other silvery spots; shield of the female longer than broad ([fig 158 e]). A. americanum.
cc. Hypostome small, without teeth, venter without furrows; body often with coriaceous shields, posterior margin of the body never crenulate (i.e. without festoons); no eyes. GAMASOIDEA.
d. Parasitic on vertebrates; mandibles fitted for piercing; body sometimes constricted. Dermanyssidæ.
e. Anal plate present. Dermanyssinæ.
f. Body short; legs stout, hind pair reaching much beyond the tip of the body. On bats. Pteroptus Dufour.
ff. Body long; hind legs not reaching beyond the tip of the body.
g. Peritreme on the dorsum, very short; body distinctly constricted. Ptilonyssus Berl.
gg. Peritreme on the venter, longer; body not distinctly constricted.
h. Mandibles in both sexes chelate. Parasitic on bats, mice and birds ([fig. 150, h]). Liponyssus Kol.
The species L. (= Leiognathus) sylviarum frequents the nests of warblers. An instance is on record of these mites attacking man, causing a pruritis.