Arachnids, or, spiders (arachnida)

To arachnids, or arachnids are all ground chelicerae, comprising approximately 35000 species, from 9 to 13 units. Stop for spiders, Scorpions and phalanges.
For the life of spiders important is web serving them refuge or loucim device used for weaving egg cocoon and wintering bag, explode juvenile survival in adverse conditions, which plays a role in the complex process of mating and breeding, foraging and so on, the Web is very strong. To break it is necessary to apply a force from 40 to 261 kg per 1 mm,2 - sectional threads.
Spider machine with developed spider gland is located at the spider's abdomen. Abdominal legs, turned into a spider warts, brought the secret out glands. Dissected movable limbs of cephalothorax adapted for spinning the web.
A variety of color spiders, especially tropical; among them are many brightly coloured plain or with a complex picture: there are bright red, black with red abdomen, different shades of green, sometimes yellow, brown, and other combinations of tones. Golovogrud covered with rigid plate on the front of 4 pairs of eyes. The sight is imperfect, especially in teretnih forms. The jumping spiders it 90 relatively good. Short and dvoichenkova of helicity serve to protect, catching, killing, kneading and tear of production. (Often or sickle-end segment, pagebase, included in the groove on the basic segment like the blade of a penknife. Duct agroproducers glands opens at the end of it.
Some spiders - chetyrehrjadnye, breathe easy, others delegacia, breathe with lungs and trachea, third - belgachia through the trachea.
Central nervous system spiders are concentrated. In a difficult situation plays an important role sense. Touch using hair covering the body and appendages. On the palp and the limbs to abi - special hairs, feeling a slight breath of air. Vibration spider threads are perceived trichomoniasi as rhythmic fluctuations with a wide range of frequencies. Lyre-shaped and totalnie bodies are used to smell and function taste body; in the walls of the throat has the taste cells. Interesting protective reaction: disturbed spiders fall "and the earth "and spider threads or (make fast oscillating movements on the network, and then the contours of their bodies indistinguishable. A kind of mimicry - external similarity with others, well protected animals.