The head has five pairs of appendages, including mouthparts, antennae, and antennules. They start by lashing each other with their antennae and flaring their mandibles. Insects have olfactory receptors on their antennae. The head bears two threadlike antennae and a pair of beady eyes. Cicadas have prominent eyes set wide apart, short antennae, and membranous front wings. Shrimp are swimming crustaceans with long narrow muscular abdomens and long antennae. Spiders have no wings and no antennae. Antennae or hairs on the organism pick up particle motion. The males have feathery antennae versus the thin antennae of females. They have three ocelli and short antennae. There are no hairs or arista arising from the antennae. An aft mast was installed to accommodate various communication antennae. Females also have more triangular faces with shorter antennae. They have large compound eyes, two ocelli, and long, flexible antennae. Caterpillars have short antennae and several simple eyes.