Spider glossary

Abdomen

The posterior division of the spider body, comprising the pedicel and usually largely unsegmented saclike portion bearing the spinnerets.

Abdomen

The posterior (rear) of the two major divisions of the body of a spider.

Accessory claws

Serrated, thickened hairs near the true claws in some spiders.

Anal tubercle

A small projection, dorsal to the spinners, carrying the anal opening.

Anal tubercle

The small caudal tubercle bearing the anal opening; the postabdomen.

Annulations

Rings of pigmentation around leg segments.

Antennae

The segmented sensory organs often termed "feelers," borne on the heads of insects, crustacea, et cetera , but missing in all arachnids.

Anterior

Nearer the front or head end.

Appendages

Parts or organs (such as legs, spinnerets, chelicerae) that are attached to the body.

Arachnida

A principal division, or Class, of the air-breathing arthropods, the arachnids, including the scorpions, mites, spiders, harvestmen, etc.

Arachnologist

One who studies the arachnids.

Araneae

The ordinal name of all spiders; same as Araneida.

Araneology

The branch of zoology that treats only of the spiders. Arthropod.The jointed-legged animals, such as centipedes, millipedes, insects, crustaceans, spiders, scorpions, and many other less well-known types; the members of the Phylum Arthropoda.

Attachment disc

The series of tiny lines that serve to anchor the draglines of spiders.

Autophagy

The eating of an appendage shed from the body by autotomy or otherwise.

Autospasy

The loss of appendages by breaking them at a predetermined locus of weakness when pulled by an outside form; frequent in spiders and arachnids.

Autotomy

The act of reflex self-mutilation by dropping appendages; unknown in the arachnids.

Ballooning

Flying through the air on silken lines spun by spiders.

Ballooning

Aeronautical dispersal by means of air currents acting on strands of silk.

Book lung

An air-filled cavity, containing stacks of blood-filled leaves, opening on the underside of the abdomen.

Book lungs

The respiratory pouches of the arachnids, filled with closely packed sheets or folds to provide maximum surface for aeration; believed to be modified, insunk gills.

Branchial operculum

A sclerotized, hairless plate overlying the book lung.

Calamistrum

The more -or less extensive row of curved hairs on the hind metatarsi, used to comb the silk from the cribellum.

Calamistrum

A comb-like series of hairs on metatarsus IV of cribellate spiders

Carapace

The hard dorsal covering of the cephalothorax in the Arachnida

Carapace

The exoskeletal covering, or shell, over the dorsal (upper) surface of the cephalothorax.

Cardiac mark

An elongate midline mark on the anterior, dorsal surface of the abdomen which overlies the heart.

Catalepsy

The action of feigning death; induced by disturbance.

Cephalothorax

The united head and thorax of Arachnida and Crustacea.

Cephalothorax

The anterior (front) of the two major divisions of the body of a spider.

Chelicerae

The pincerlike first pair of appendages of the arachnids; in spiders two-segmented, the distal portion or fang used to inject venom from enclosed glands into the prey.

Chelicerae

The jaws, each one comprising a large basal part and a fang

Chitin

A linear homopolysaceharide found as the characteristic molecule in the cuticle of arthropods. The molecules are layered in chains and cross-linked to form the strong, lightweight basis of the cuticle.

Chorion

The outer covering or shell of the spider or insect egg.

Claw tuft

A bunch of hairs at the tip of the leg tarsus in spiders with only two claws.

Claw tufts

The pair of tufts of adhesive hairs present below the paired claws at the tip of the tarsi of many spiders.

Clypeus

The area between the anterior row of eyes and the anterior edge of the carapace.

Colulus

The slender or pointed appendage immediately in front of the spinnerets of some spiders; in other greatly reduced or seemingly missing; the homologue of the anterior median spinnerets or cribellum.

Colulus

A small midline appendage or tubercle arising just in front of the anterior spinners in some spiders.

Conductor

A semi-membranous structure in the male palp which supports and guides the embolus in insemination.

Condyle

A smooth, rounded protuberance sometimes present on the outer side of the chelicera, near its base.

Coxa

The basal segment of the leg by means of which it is articulated to the body.

Coxa

The segment of leg nearest the body; modified in the palp to form the maxilla.

Coxal glands

The excretory organs of arachnids, in spiders located opposite the coxae of the first and third legs, that collect wastes into a saccule and discharge them through tubes opening behind the coxae; homologous with the nephridia of Peripatus, etc.

Cribellum

A sievelike, transverse plate, usually divided by a delicate keel into two equal parts, located in front of the spinnerets of many spiders; the modified anterior median spinnerets.

Cribellum

A spinning organ just in front of the spinners which appears as a transverse plate. Only present in cribellate spiders, which also have a calamistrum.

Cuticle

The hard outer covering of an arthropod.

Cymbium

The broadened, hollowed-out tarsus of the male palp within which the palpal organs are attached.

Deutovum

The resting, spiderlike stage following the shedding of the chorion of the egg; the second egg.

Distal

Pertaining to the outer end, furthest away from the body or point of attachment.

Dorsal

Pertaining to the upper surface.

Dorsum

In general, the upper surface.

Dorsum

The upper surface.

Ecdysis

The process of casting the skin; molting.

Ecdysis

Moulting; the periodic casting off of the cuticle.

Embolus

The structure, in the male palp, containing the terminal part of the ejaculatory duct and its opening. It may be very small, or long, whip-like or coiled and is sometimes divided into several structures.

Endite

The plate borne by the coxa of the pedipalps of most spiders, used to crush the prey; the maxilla.

Entelegyne

The group of spiders in which the females have an epigyne.

Epigastric fold

A fold and groove separating the anterior part of the ventral abdomen (with epigyne and book lungs) from the posterior part.

Epigyne

A more or less sclerotized and modified external structure associated with the reproductive openings of adult females of most spider species.

Epigynum

The more or less complicated apparatus for storing the spermatozoa, immediately in front of the opening of the internal reproductive organs of female spiders.

Exoskeleton

The hard, external, supportive covering found in all arthropods.

Exuviae

The parts of cuticle cast off during moulting.

Fang

The claw-like part of each chelicera; the poison duet opens near its tip.

Femur

The thigh; usually the stoutest segment of the spider's leg, articulated to the body through the trochanter and coxa and bearing the patella and remaining leg segments at its distal end.

Femur

(p1. Femora; adj. femoral) The third segment of the leg, counting from the body.

Folium

Any pattern of pigment on the dorsum of the abdomen which is fairly broad and leaf-shaped.

Fovea

A short median groove on the thoracic part of the carapace which marks the internal attachment of the gastric muscles.

Genitalia

All the genital structures.

Gossamer

A light film of silk threads, or groups of these floating through the air.

Hackled band

The composite threads of the cribellate spiders, spun by cribellum and combed by the calamistrum.

Haematodocha

A balloon of elastic connective tissue between groups of seletites in the male palp which distends with blood during insemination causing the selerites to separate and rotate.

Haplogyne

The group of spiders in which the females have no epigyne.

Head

The part of the carapace carrying the eyes which is separated from the thorax by a shallow groove.

Labium

The lip, under the mouth opening and between the maxillae, attached to the front of the sternum.

Lanceolate

Tapering to a point.

Lateral

Pertaining to the side.

Lyriform organ

A sensory organ near the distal end of limb segments formed of a group of parallel slit organs.

Maxilla

The mouthparts on each side of the labium which are the modified coxae of the palps..

Median

In the midline or middle.

Median apophysis

A selerite arising from the middle division of the male palpal organs.

Metatarsus

(p1. metatarsi; adj. metatarsal) The sixth segment of the leg, counting from the body.

Orb web

A two-dimensional web, roughly circular in design (and, strictly speaking, a misnomer). Silk threads radiate like spokes from a central hub. These are then overlaid with a spiral of silk, running from the periphery almost to the hub.

Palp

Short for pedipalp. The appendage arising just in front of the legs, the coxa of which also forms the maxilla. It has no metatarsal segment and in adult males is greatly modified for the transfer of semen.

Palpal organs

The more or less complex structures fs)und in the terminal part of the adult male palp. They comprise groups of sclerites separated from each other and the cymbium by up to three haematodochac and contain the semen reservoir which opens via ducts through the tip of the embolus.

Paracymbium

A structure in the male palp branching from, or loosely attached to, the cymbium.

Patella

(pl. Patellae, (adj. patellar) The fourth segment of the leg or palp, counting from the body.

Pedicel

The narrow stalk connecting the cephalothorax and the abdomen.

Pheromone

A chemical secreted by an animal in minute amounts which brings about a behavioral response in another, often of the opposite sex.

Phylogenetic

Pertaining to evolutionary relationships between and within groups.

Posterior

Near the rear end.

Process

A projection from the main structure.

Procurved

Curved as an arc having its ends ahead of its center.

Prolateral

Projecting from, or on, the side facing forwards.

Proximal

Pertaining to the inner end; closest to the body or point of attachment.

Punctate

Covered with tiny depressions.

Recurved

Curved as an arc having its ends behind its center.

Reticulated

Like network.

Retrolateral

Projecting from, or on, the side facing backwards.

Rugose

Rough, wrinkled.

Scape

A finger-, tongue-, or lip-like projection from the midline of the female epigyne.

Sclerite

Any separate sclerotized structure connected to other structures by membranes.

Sclerotized

Hardened or horny; not flexible or membranous.

Scopula

(pl. scopulae) A brush of hairs on the underside of the tarsus and metatarsus in some spiders.

Scutum

A hard, often shiny, sclerotized plate on the abdomen of some spiders.

Septum

A partition separating two cavities or parts.

Serrated

Saw-toothed.

Sexual dimorphism

A difference in form, color, size, etc., between sexes of the same species.

Sigillum

(pl. sigilla) An impressed, sclerotized spot, often reddish-brown. Often present on the dorsal surface of the abdomen and marking points of internal muscle attachments.

Slit organ

A stress receptor in the exoskeleton

Sperm induction

The process of transferring the spermatozoa from the genital orifice beneath the base of the abdomen into the receptacle in the male palpus.

Sperm web

A web of few or many threads on which male spiders deposit the semen preparatory to taking it into the palpus.

Spermathecae

The vessels or receptacles in the epigyna of female spiders that store the spermatozoa of the males.

Spermathecae

The sacs or cavities in female spiders which receive and store semen.

Spermatozoa

The mature sperm cells.

Spiderling

A tiny, immature spider, usually the form just emerged from the egg sac.

Spiderling

The nymphal or immature spider, generally resembling the adult, hut smaller; fully mobile and no longer dependent on yolk.

Spine

A thick, stiff hair or bristle.

Spinnerets

The fingerlike abdominal appendages of spiders through which the silk is spun.

Spinners

Paired appendages at the rear end of the abdomen, below the anal tubercle, from the spigots of which silk strands are extruded.

Spiracle

A breathing pore or orifice leading to tracheae or book lungs.

Spiracle

The opening of the tracheae on the underside of the abdomen.

Stadium

The interval between the molts of arthropods; instar; a period in the development of an arthropod.

Sternum

A sclerotized plate between the coxae marking the floor of the cephalothorax.

Sternum

The heart-shaped or oval exoskeletal shield covering the under surface of the cephalothorax.

Stridulating organ

A file-and-scraper for sound production; may be variously located on chelicerae, palps, legs, abdomen and carapace.

Subadult

Almost adult; the last instar before maturity.

Synonym

Each of two or more scientific names of the same rank used to denote the same taxon. The senior synonym is the name first established.

Tarsus

The foot; the most distal segment of the legs, which bears the claws at its tip.

Tarsus

(pl. tarsi; adj. tarsal) The most distal (or end) segment of a leg or palp.

Taxon

Any taxonomic unit (eg. family, genus, species).

Taxonomy

The theory and practice of classifying organisms, part of systematics, the study of the kinds and diversity of organisms.

Tergites

Dorsal sclerites on the body; the hard plates on the abdomen of the atypical tarantulas that indicate the segmentation.

Thorax

The second region of the body of insects that bears the legs; in spiders, fused with the head to form the cephalothorax.

Thorax

That part of the cephalothorax behind the head region and separated from it by a shallow groove.

Tibia

The fifth division of the spider leg, between the patella and metatarsus.

Tibia

(pl. Tibiae adj. tibial) The fifth segment of the leg or palp counting from the body.

Tracheae

The air tubes in insects; in spiders, tubular respiratory organs of different origin; by many thought to be modified book lungs.

Tracheae

Tubes through which air is carried around the body and which open at the spiracles.

Trichobothrium

(pl. trichobothria) A long, fine hair rising almost vertically from a socket on the leg. Trichobothria detect air vibrations and currents.

Trochanter

The second segment of the leg or palp, counting from the body.

Ventral

Pertaining to the underside.

Zygote

The fertilized egg.