Myth 4: You can always tell a spider because it has eight legs. Fact: Not right. Scorpions, harvestmen, ticks, and in fact all arachnids (not just spiders) have four pairs of legs. Insects have three pairs. Also, sign that I said "four pairs" instead of "eight." The number of leg pairs (one pair per leg-attitude segment) is more significant than individual legs, which can be lost.
Most spiders could not wound humans because their fangs are too small. Fact: That may actually be firm of a few of the minimum spiders. However, there are well-documented soul gnaw gear from spiders as small as 3 millimeters long. (The bites caused no ill property, of course!)