Mecaphesa Moving Eyes

Jumping spiders and crab spiders are among the few spiders that can move their "main" eyes. The main eyes of an eight-eyed spider are the anterior middle two eyes. Here you see the main eyes of an adult male Mecaphesa celer moving. Spiders don't have ball-and-socket eyes like we do. Instead they just move their retinas. Crab spiders make images with these moving eyes, but the images are in focus only at about a centimeter. Most Mecaphesa celer are pale yellow or tan in color. The green abdomen makes this one unusual. Some young (elementary school) arachnologists found this spider in a patch of ragweed during a program I was conducting in Austin, Texas, on May 23, 2013. It has a body length of 3mm, or just under 1/8 inch.