508 
xYRACHNIDES. 
lung and straight; dark brown, and covered with ciliated hairs. 
Inhabits England and France, under stones. 
TRIBE III.-PHALANGITA. 
With slender filiform palpi, terminating in a small hook.—It 
contains the following genera :—8. Phalangium ; 9. Trogulus ; 
and 10. Siro. 
Genus 8. — PHALANGIUM.— Linnaeus. 
Generic Character. —The head and abdomen united under a 
common skin; the abdominal folds having the appearance of an- 
nulations; with articulated, geniculated, and protruding mandi¬ 
bles, ending in forceps ; pedipalpi filiform, consisting of five 
joints, the last ending in a small hook; eight feet; labium ex¬ 
ternal, with a hole in each side ; two eyes supported on a com¬ 
mon tubercle; body ovoid or rounded. 
Phalangium cornulum. — The Horned Phalangium. 
Plate XCVI. fig. 11. 
Reddish ash-coloured above; the mandibles and antennae 
whitish. Inhabits Europe, in walls, &c. 
TRIBE IV.-ACARIDES. 
Body ovate or globular; palpi filiform and protruding; eyes 
small, feet eight and hairy, terminated by from two to three 
hooks_The genera are, 11. Trombidium ; 12. Erythrseus; 
13. Gamasus; 14. Cheyletus; 15. Uropoda; 16. Acarus; 
17. Oribata; and 18. Eylais. 
Genus 16.—ACARUS.— Fabricius. 
Generic Character. —With a very soft body, furnished with a 
naked mouth; palpi short or concealed; tarsi terminated by a 
vascular ball. 
Acarus domesticus. — The Cheese Mite. 
Plate XCVII. fig. 1. 
Body ovate, yellowish-white, beset with long remote hairs. 
Inhabits cheese and old flour, in England. 
