633 TRACHEARIA. 



The Scorpions, Scorpionida, form the larger part of this di- 

 vision. These have a jointed, tail-like extension of the abdo- 

 men, ending in a curved spur. (Plate XV. fig. I9a.) They are 

 found in temperate as well as tropical regions, living under stones, 

 in damp places, and even in houses. They are particularly fond 

 of the eggs of spiders and insects. Their sting is said to be- 

 come increasingly poisonous as the animal grows older. 



The generality of Scorpions, as Scorpio Europaus, have six 

 eyes ; but there are some of the most formidable kind, as Scor- 

 pio afer, the AFRICAN SCORPION, which have eight. 



SECOND ORDER. TRACHEARIA, (Gr. TQa%eia, tracheia, a wind- 



pipe.) 



This includes those forms of the class which have two or four 

 eyes, and breathe by means of trachial tubes or air-pipes, simi- 

 lar to those of Insects. These include, (1) the various forms of 

 Mites, Acarida, such as the CHEESE- MITES, Acarus, the Itch- 

 Mite, A. scabiei, (of itch,) named from the cutaneous disease of 

 which it is the origin ; the Su&AR-MiTE, A. saccharinum, found 

 in the brown sugar of commerce ; the RED SPIDER, A. tellarius, 

 the pest of hot houses and green houses, &c. Camphor and 

 sulphur are the best remedies for removing these minute, and 

 some of them almost microscopic animals. These are not now 

 considered as ranking among insects, differing from them as they 

 do, in structure, and having in most cases, like spiders, eight feet, 

 while no insect has more than six feet. (2) TICKS, Ricinia, 

 while no insect has more than six feet. (2) TICKS, Ricinia, (Lat. 

 ricinus, a tick,) embracing the genus Ixodes, (Gr. sticky,) (PI. 

 XV., fig. 19.) some species of which are free, and others parasitic. 

 The latter are without eyes. They are well known from attack- 

 ing sheep, cows, horses, dogs, and even tortoises, burying their 

 suckers so deeply in the skin that they cannot be reniDved with- 

 out tearing the flesh. They deposit a prodigious quantity of 

 eggs, which are discharged from the mouth. (3) SHEPHERD 

 SPIDERS, or Harvest-men, Phalangida, genus Phalangium, (Lat. 

 a spider,) of which the greater part live upon the ground, on 

 plants, or at the roots of trees, and are very active ; others, which 

 are less active, hide themselves between stones, or in mosses. 

 Their legs are long and slender, the tarsi consisting of more than 

 fifty joints. These spider-like creatures are known as Harry- 

 long-legs. (4) The SEA SPIDERS, Nymphonida, are also in- 

 cluded in this order, though sometimes referred to the class 

 Crustacea,. Our limits do not allow us to enumerate all the 

 families, or to- give any further particulars respecting those 

 which are mentioned. 



