The Phylum Arthrodopa includes the Class Insecta. Other non-insect classes include spiders, scorpions, whipscorpions, harvestmen, ticks, mites, sea spiders, crustaceans, millipedes, centipedes, pauropods and symphylans. Orb Weaver Spider Araneus spp. Araneae Araneidae Orb web spiders are a large and diverse group of spider ranging in size and coloration. Most of them spin an orb web characterized by expanding circles of sticky silk thread hung from support lines that meet at a central point.
Females are usually considerably larger than males.
I found this colorful spider in the marshy regions of the San Francisco Bay Area. She had spun her web on a low shrub and was patiently waiting in a protective silk retreat with handy trigger lines attached to the center of the web awaiting a characteristic tug signal when an unfortunate insect becomes entangled. Many Orb Web spiders build a new webs each night, often by touch alone. As a defensive strategy, they frequently drop to the ground when disturbed.