Morphology of the external sense organs on the adult Lycosoides coarctata (Araneae: Agelenidae) inhabiting Assiut Governorate, Egypt. 

Spiders are equipped with a large number of sense organs, which respond to various sensory stimuli. The spider's body hair and spines are high sensitive to touch and to vibrations. Spiders can feel a puff of air so gentle that it only stirs one hair. Spiders do not have ears, but have an excellent hearing. They pick up sound vibrations with tiny hairs on their legs and bodies. A spider can "hear" the vibrations of an insect walking along the ground or onto a web. They can tastes and smells with its feet. Scanning electron microscopic studies illustrate the presence of different types of hairs and sensilla on different parts of adult males and females of Lycosoides coarctata . There are two stimuli affected to spiders, mechanical and chemical stimuli. Here we focus on the different types of sensilla: the mechanosensory setae, trichobothria, slit sensilla, lyriform organs, trichoid sensilla, sensilla placodea, sensilla styloconica and chemosensory setae. Trichobothria have a cup-like socket and a long hair-like projection. Trichobothria present on all walking legs, pedipalps, chelicerae and are the air movement sensors of spiders.