Acarina 



26s 



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



gopher tortoise in Florida A. tuberculatum 



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. 

 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 ( =mixtimi). 



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. 



]• 



JJ- 







Jntcrna,l spur 

 CoKcc -Zr. 



Coxa£ s/iMJis 



Rhipicentor bicornis, ventral aspect, male. 

 Warburton. 



After Nuttall and 



:. 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 DERMANYSSlNiE. 



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. 



