Orb Weaver Identification Chart: 14 Species by Underside

If the spider is sitting in a round, wheel-shaped web of straight spokes and a spiral, it is almost certainly an orb weaver. University of Kentucky entomologists describe orb weavers as the spiders that weave the classic orb web of rays and spirals of silk. Other clues:

• Position. The spider rests at the centre of the web, or hides in a curled leaf or crevice at the edge with a signal line running to the hub so it feels prey arrive (UC IPM; Missouri Department of Conservation).
• Clumsy off the web. Orb weavers have poor eyesight and have trouble walking on anything but webs (University of Kentucky).
• Eyes and claws. Eight similar eyes and three claws on each foot, which let them walk on the non-sticky threads (Wikipedia).
• Rarely indoors. They are often on or near outside walls, but rarely come inside (University of Kentucky).

For spiders that are not orb weavers, see spider identification.

The top of an orb weaver's abdomen is often wildly variable: Missouri's marbled orbweaver alone ranges from marbled swirls to zigzags or a single big black spot. The iNaturalist forum's orb weaver wiki points out that the underside varies much less, and underside photos are often the only ones people get of a spider sitting in its web. The same wiki is honest about limits: certainty to species usually requires examining the genitalia under magnification, so a cluster of matching features is the goal, not one mark.

Underside marks are from the iNaturalist forum wiki; sizes and ranges from the sources named.

• **Yellow garden spider (*Argiope aurantia*):** top of abdomen yellow and black; legs usually solid black at the tips and brown near the body; one solid yellow stripe on the sternum. Females 19 to 28 mm, males 5 to 8 mm; web 50 to 100 cm across with a white zigzag stabilimentum (Penn State Extension).
• **Banded garden spider (*Argiope trifasciata*):** legs always banded, never two-toned; sternum sometimes with paired yellow marks.
• **Cross orbweaver (*Araneus diadematus*):** white marks bracketing the underside, straighter and more angular than *Larinioides*; dark sternum. On top, white spots forming a cross. Native to Europe, introduced to North America; females 6.5 to 20 mm (Wikipedia).
• **Marbled orbweaver (*Araneus marmoreus*):** yellow brackets underneath; legs orange near the body. Females 1/2 to 3/4 inch (Missouri Department of Conservation).
• **Shamrock orbweaver (*Araneus trifolium*):** adults dark reddish underneath with no bracket marks.
• **Barn orbweaver (*Araneus cavaticus*):** brackets like the cross orbweaver, but longer legs with dark bands.
• **Giant lichen orbweaver (*Araneus bicentenarius*):** a mark like a T with a wide triangular base and bulbous arms.
• **Spotted orbweaver (*Neoscona crucifera*):** white marks like the bottom halves of square brackets; pale sternum edged with dark, unlike *Araneus*. Females 9.5 to 19 mm, often rusty-red or golden orange; builds at night and eats the web each morning (Wikipedia).
• **Western spotted orbweaver (*Neoscona oaxacensis*):** bracket marks more often broken into separate pieces.
• **Arabesque orbweaver (*Neoscona arabesca*):** a pair of white marks on each side underneath, plus dim white marks towards the head.
• **Furrow orbweaver (*Larinioides cornutus*):** white brackets more curved than *Araneus*; underside black throughout.
• **Grey cross spider (*Larinioides sclopetarius*):** a dark band in the middle of the second-to-last segment of the rear legs; common on buildings.
• **Bordered or ornamental orbweaver (*Larinioides patagiatus*):** curved brackets, often some red on the legs, less often on buildings.
• **Spinybacked orbweaver (*Gasteracantha cancriformis*):** unmistakable: six spine-like points on a wide, hard abdomen, white or yellow with black spots; females 5 to 9 mm long and 10 to 13 mm wide (Wikipedia).

Many orb weavers are most noticeable in late summer and fall. Missouri's marbled orbweaver is most active in late summer through fall, and adults are killed by the first freezes while egg sacs overwinter (Missouri Department of Conservation). The spotted orbweaver is most conspicuous in late summer and early fall, and is mostly nocturnal (Wikipedia).

Time of day is a useful clue. A big orb web across a porch light at night that is gone by morning points to a night builder such as the spotted orbweaver, which builds at night and eats the web each morning (Wikipedia). A web in full sun in the garden with a zigzag band points to *Argiope*: University of Kentucky notes the black and yellow garden spider builds in open, sunny places in gardens and tall grass. For the egg sacs they leave behind, see spider egg sac identification.

Orb weavers are not a medical concern for people. The Missouri Department of Conservation says orbweavers don't bite unless molested and their bites are not dangerous. Penn State Extension says yellow garden spiders are not known to be medically important and a bite would likely cause no more discomfort than a bee or wasp sting. The cross orbweaver bites only if cornered or provoked (Wikipedia). University of Kentucky entomologists note that only a few spiders, such as the black widow and brown recluse, have venom that is very toxic or harmful to humans.

As with any bite or sting, get medical care for trouble breathing, facial swelling or spreading redness, and see spider bite identification for what a spider bite does and does not look like.

Not rare at all. Araneidae is one of the largest spider families, with 4,710 species in 197 genera as of January 2026 (Wikipedia). Locally the numbers are large too: the Montana Field Guide lists more than two dozen orb weaver species for that state, Missouri has 14 *Araneus* species, and the black and yellow garden spider is common statewide in Missouri (Missouri Department of Conservation). The one non-native species on the Montana list is the cross orbweaver.

Usually there is no need. UC IPM says spiders are mostly beneficial because they eat large numbers of nuisance and pest insects, and orb weavers catch whatever flies into their webs. If a web is in a doorway, UC IPM suggests removing webs from the outside of the house with a broom or high-pressure hose, vacuuming any spider and web indoors, and sealing cracks and keeping screens in good repair.

Take two photos without touching the web: one of the underside through the web, and one of the top from behind. Add one of the whole web and, if you can, the legs, since leg banding separates the two *Argiope* species and the grey cross spider. InsectLens uses these views to name the spider.

Research and drafting for this page used AI assistance. Every figure, date and quotation was then checked line by line against the sources listed at the bottom of the page, each of which was opened while writing. Nothing here is a diagnosis. If a bite, sting or contact with an insect is followed by trouble breathing, swelling of the face or throat, spreading redness, fever or any symptom that worries you, get medical care; in the United States Poison Help (1-800-222-1222) is free and open 24 hours a day.