Yellow garden spiders are large, orb-weaving arachnids, meaning they spin a circular web. Most spiders have two claws on each foot, but orb weavers have an additional claw to help them spin their complex webs. In females, the top side of the abdomen is black with symmetrical patches of bright yellow. The legs are reddish brown at the base and black toward the tips. Males are less striking in appearance—they are smaller with brownish legs and less yellow colouration on their abdomens. Females average 0.75 to 1.1 inches (19 to 28 millimetres) in body length, which is up to three times larger than the males.