266 
Hominoxious Arthropods 
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. gallinae. 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. 
. Halarachnin^;. 
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 in¬ 
sects . Uropodid^e. 
154 . Rhieephalus sanguineus, male. 
After Nuttall and Warbur- 
ton. 
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 .Gamasidae. 
This family contains a number of genera, some of which are found 
upon mammals, though the majority affect only other artho- 
pods. One species, Laelaps stabularis, frequents the bedding 
in stables, and in one instance at least, has occasioned irri¬ 
tation 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. 
d. Aquatic species.HYDRACHNOIDEA 
dd. Not aquatic. 
