Acarina 



26$ 



i. Projections of coxa I blunt and short. Large species on the 



gopher tortoise in Florida A. tuber culatum 



ii. Projections of coxa I longer, and at least one of them sharp 



pointed; second segment of palpus twice as long as the 



third; coxa IV of the male with a long spine. 



j. Porose areas nearly circular; shield of both sexes pale 



yellowish, with some silvery streaks and marks, and 



some reddish spots; shield of female as broad as long. 



A. cajennense ( =mixtum). 



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 fe- 

 male longer than broad (fig 158 e). .A. americanum. 



153. Rhipicentor bicornis, ventral aspect, male. After Nuttall and 

 Warburton. 



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 DERMANYSSID^E. 



e. Anal plate present DERMANYSSIISLE. 



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 con- 

 stricted Ptilonyssus Berl. 



gg. Peritreme on the venter, longer; body not distinctly con- 

 stricted, 

 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. 



