Acarina 
265 
i. Projections of coxa I blunt and short. Large species on the 
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, 
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. 
internal spur 
Exttrn&l spu^n 
Kcc 31 
Ccxjx- ?rr 
CmcxK 2 Y. 
•Spi cac /e— 
153 . Rhipicentor bicornis, ventral aspect, male. After Nuttall and 
Warburton. 
rrcPcoC 
:. 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. DERMANYSSiNbE. 
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. 
