Glossary of Spider Terms

Annulated—colored with darker banding and frequently referring to banded legs

Antivenom—a chemical antidote designed to counteract the effects of specific venom; also called antivenin

Ballooning—a behavior exhibited by some newborn arthropods wherein a recently hatched arthropod spins out some silk, which then catches the wind and carries the immature arthropod for a distance

Carapace—the hard integument forming the dorsal surface of the cephalothorax (not including the appendages)

Cephalothorax—the fused head/thorax region, as found in spiders

Chelicerae—(sing., “chelicera”) the front jaws of a spider consisting of a stout basal segment and a terminal fang

Chevron—a figure, pattern, or object having the shape of a “V” or an inverted “V”

Cytotoxin—any material that is destructive to cells

Distal—that portion of a structure that is farther from the central body (e.g., a human wrist is distal to the elbow)

Edema—excessive fluid buildup in cells or tissues

Envenomation—the introduction of venom into the body of another organism as a defense or feeding mechanism

Erythema—a flush on the skin surface produced by congestion within the capillaries

Femora (femur)—the third segment of the spider leg following the coxa and trochanter

Folium—a pattern or design on the abdomen surface

Millimeter—metric unit of length (25 mm = 1 inch)

Necrotic—tissue in a dead or decaying condition

Neurotoxin—any material that causes damage to the nervous system

Palps—(also “palpi” or “pedipalps”) paired, forward-projecting sensory organs of spiders located behind the chelicerae but in front of the legs; the second appendages of the cephalothorax

Papules—small, inflamed, congested areas of the skin

Patella—the fourth segment of the spider leg following the coax, trochanter, and femora (femur)

Penultimate instar—the next-to-last developmental stage of an arthropod before it molts into an adult

Procurved—eyes that are arranged in an upside-down “U” when viewed from the front

Pruritus—itching skin

Spinnerets—appendages that produce silk and are located at the posterior portion of the abdomen

Stabilimentum—a heavy band of silk deposited in the center of the web of some of the orb weaving spiders

Tarsi—the last or terminal segments of a spider’s legs bearing two or occasionally three claws

Tibia—the fifth segment of the spider leg following the patella and preceding the tarsi

Venom—a poisonous substance that is produced by various animals (e.g., spiders, scorpions, and other arthropods; snakes and certain lizards) for defense or to subdue prey; can cause pain and swelling but rarely fatality when injected into humans

Venter—the underside of the spider; typically referring to the abdomen