SPIDERS— MITES AND MILLIPEDE 273 



Since mites of some kind are to be met with everywhere, they 

 may be looked for in buildings. A noisome creature is the common 

 bird-mite (Dei-man yssus avium), which lives in pigeon-cotes, fowl-houses, and bird- 

 cages, where it sucks the blood of the slumbering inmates, turning reddish brown 

 in colour from the quantity swallowed. Spotted with white, it is specially dis- 

 tinguished by the very long terminal joints of the legs. In the familiar cheese- 

 mite (Tyroglyphus siro) the general colour is whitish yellow, with the beak 

 and legs brownish, occasionally two dark spots on the back, and the head sur- 

 mounted by a pair of bristles. Nearly allied is the flour-mite (T. fariv.ce), which 

 lives in stale flour, and resembles the cheese-mite in many respects, although 

 distinguished by the form of the thorax. The fine powder found in boxes of old 

 figs and prunes is composed almost entirely of these mites. 



The so-called harvest - spiders are minute, long, thin-legged 



' creatures, with short, rounded, and unstalked, although jointed, 



abdomen. Among them the common weaver harvester (Phalangium parietinum) 



is often found in houses, walls, and gardens ; its principal colour is light brown, 



but on the middle of the abdomen it has an almost rhombic dark brown mark. 



A single species of millipede, the rough-tailed brush-millipede 

 ' (Polyxenus lagurus) so seldom seen, is an inmate of human dwell- 

 ings, being often found in the crevices of walls, though it also lives under the 

 bark of trees. Consisting of a series of soft circular segments, covered with tufts 

 of hair, it has a brown body, terminating in a white brush, so as to look much 

 like the larva of the cabinet-beetle. The wall woodlouse (Oniscus muraria) is 

 a crustacean, being one of the isopods. 



WALL WOODLOUSE. 



VOL. I. — 1 5 



