can inject venom that is life-threatening to humans. The stings are not part of a deliberate attack, but are mainly the result of brushing against the spines. However, many species whose larvae are armed with such bristles have behavioral patterns adapted to present the urticating hairs as a defensive threat and to inflict them on any perceived attackers. For example, many larvae in the family Lasiocampidae bear dense bands of short stinging bristles across their thoracic segments. The bristles are normally retracted into a shallow fold in the skin, but if the caterpillar is disturbed, it everts the folds and displays the bristles, which are usually of a contrasting color. If seriously stimulated or gripped, lasiocampid larvae are likely to lash about, forcing the stinging bristles into any vulnerable organ within reach. Many other species of larvae lack any such localized concentrations of bristles and are armed more generally with urticating hairs; even so, they too will lash about frantically if disturbed, making them difficult to handle without suitable equipment. Toxins from the broken bristles may spill out, causing dermatitis on the surface of the skin. For brown-tail moths (Euproctis chrysorrhoea) native to Europe and invasive in other parts of the world, bristles are shed or broken off during molts and can be wind-borne, so that direct contact with live or dead larvae is not required to trigger a rash. In spite of such defenses, some species of birds feed avidly on "hairy" caterpillars. Usually they grab them in their beaks and scrub them on the ground until the majority of the bristles have been stripped or damaged, but at least some species of cuckoos apparently collect the bristles in the digestive tract until they form pellets that can be regurgitated. Examples of avian predators other than cuckoos that feed on "hairy" caterpillars include at least tens of species from several continents. In tarantulas Urticating hairs (setae) are found in about 90% of the species of tarantula (spiders of the family Theraphosidae) found in the New World. They are not found in tarantulas from other parts of the world. Development Urticating hairs do not appear at birth but form with each consecutive molt, widening from molt to molt and outwardly presenting themselves around areas of more dark bristles on the upper back part of the abdomen of juveniles. In elder ages their coloration shifts to match the main tone of