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