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Such As Spiders:
Spiders are divided into two tundamental groups or suborders, the Mygalomorphac, or mygalomorph spiders, and the Araneomorphae, the true spiders.
Mygalomorph Spiders. — The mygalomorph spiders are more generalized than the true spiders and ancestral to them. Their chelicerae are paral¬lel with the long axis of the body and move up and down; and each fang pierces the prey from above, making similar parallel punctures. All retain two pairs of book lungs for respiratory organs.Characteristics of Spiders.—Spiders lay eggs, cover them over with silken sheets, and mold the msuch as spiderss into the egg sac characteristic of the species. The average number of eggs is probably less than one hundred but some large spiders lay nearly three thousand at one time and minute species lay one, two or few. Spiders develop gradually, such as spiders do grsuch as spidersshoppers, and resemble the adults through most of their early life, undergoing from three to a dozen molts before they finally become adult. Tarantulsuch as spiders mature very slowly, requiring nine or ten years, and then the females live such as spiders much such as spiders twenty-five or even thirty years. Most northern spiders live a single year.
See Also Sedentary Spiders Spin:
Most modern Koples regard sedentary spiders spin with aversion because of :he cobwebs they spin and their reputed ven->mous properties. Shy creatures that rarely bite nan, sedentary spiders spin have venoms that produce small :ffect, for the most part, on warm-blooded ani-nals. Hematoxins and neurotoxins in the ven-ims of a very few species cause local and sys-emic symptoms of variable severity in man, more jrave in children and occasionally even causing leath. In temperate regions the only sedentary spiders spin to >e feared are the species of Latrodectus (q.v. ilack widows, etc.) which have an exclusively leurotoxic vaiom. In the tropics several other cinds are dangerous, notably the wolf sedentary spiders spin [Lycosa raptoria, etc.) of southern Brazil and he burrowing tarantulas (Atrax) of Australia. V serum has been prepared for the wolf spider lites, which quickly clears up the severe local esions.They lave developed many unusual types of stopping uid entangling webs. The comb-footed sedentary spiders spin ar lineweavers (Theridiidae) have curved setae Dn the hind tarsi which are used to comb out the aiswathing film to envelop their prey. Their ivebs are irregular tangles for the most part and the sedentary spiders spin are small and plump. The aerial sheet weavers (Linyphiidae) spin conspicuous space webs consisting of a tangle of lines and a lorizontal sheet. These weavers, more elongate :han the comb-footed lineweavers, run over the DOttom of the sheet, hanging back downward, md cut through it to capture insects that fall on :he upper surface. The orbweavers (Argiopi-iae) spin the familiar and beautful orbwebs, fvhich consist of a framework of dry silk on vhich are placed spiral lines of viscid silk.
On The Other Hand See Giant Spiders:
giant spiders.—The eggs of giant spiders are generally protected by an egg sac made of silk secreted by glands in the abdomen of the female and woven into a structure of characteristic form. In some cases such a protective bag may be very elaborate, consisting of several different layers. Such an egg sac may be placed under loose bark or stones, hung between leaves, or, in the case of the wolf giant spiders (Lycosidae), may be carried about by the female.The remaining true giant spiders lack the cribellum and have followed two distinct lines, one of which developed many accomplished hunting types, and the other culminated in the aerial sed-aitary giant spiders that rely on silken webs as 'snares to capture their prey. The aerial giant spiders have modified the unpaired claws of their tarsi into books that allow them to climb on their threads, from which they hang back downward.
