Abdomen – Hindmost section of the body of an insect or spider.
Algae – Water plant with no true stems or leaves.
Amphibian – Animal able to live both on land and in water.
Antennae – Pair of flexible sensitive projections on an insect’s head (feelers).
Aquatic – Growing or living in or near water.
Arthropod – Animal with its skeleton on the outside, having a segmented body and jointed limbs. Spiders, insects and crustaceans are all different types of arthropods.
Biocontrol (biological control) - Use of organisms to control insect pest populations.
Bug - Informal classification for any land-dwelling arthropod (insect, arachnid, crustacean, etc.)
Cellulose – Organic substance found in all plant tissues.
Cephalothorax – Two of the three major body regions (head and thorax) combined into one, as in spiders.
Cerci – Two tiny hairs at the tip of an insect's abdomen that detect movement.
Chelicerae - spider's jaws; located on the very front of a spider's cephalothorax.
Chitin – Organic substance forming a part of the exoskeleton.
Chrysalis – Capsule-enclosed pupa from which a butterfly or moth develops.
Citrus – Fruit trees such as lemon, orange, and grapefruit.
Cocoon – Silky sheath around a chrysalis; a protective wrapping.
Colony – Group of organisms usually of the same species living close together.
Complete metamorphosis – Insect changes to an adult in several stages. For example, a housefly changes from an egg to early larva, then to full-sized larva, then to a pupa and finally to an adult. When in the pupal stage, it “rests” before the final molt to become an adult.
Compound eye – Organ of vision in many insects. It contains many light-sensitive facets that make a complete image on the retina. Very useful for detecting small movements.
Cornicles – Pair of wax-secreting projections (little horns) on the back end of an aphid.
Coxa – First segment of an insect leg.
Crustacean – Animal that has a hard shell, such as a crab or shrimp.
Cuticle – Outermost layer of an insect’s exoskeleton.
Decomposer – Insect that eats dead or decayed matter.
Detritus – Decomposing or decaying organic matter.
Duff – Decomposed leaf litter.
Ecdysis – Another name for molting or shedding of the old exoskeleton.
Elytra – Sheath or covering that protects the wings of beetles.
Embryo – Organism in the earlier stages of development. An organism inside an egg is an embryo.
Entomology - Study of insects.
Exoskeleton – External supporting and protective structure of an insect.
Fang – Piercing part of the spider jaw.
Femora - Plural of femur.
Femur – Segment of an insect’s leg nearest to its body.
Filament – Fine thread or fiber.
Filiform – Thin and hairlike.
Fry – Newly hatched fish.
Gall – Growth caused by an insect on a plant. It is used for protection and food.
Grub – Thick-bodied wormlike larva of certain insects.
Halteres – Pair of balancing organs just behind and at the base of a fly’s wings.
Herbivorous – Feeding on vegetable matter; plant eating.
Holometabolism – Complete form of metamorphosis in which an insect passes through four separate stages of growth, as embryo, larva, pupa, and imago.
Hydrophobic – Repelling water.
Imago – Fully adult stage of an insect after undergoing metamorphosis.
Incomplete metamorphosis - Gradual development in three distinct stages: egg, nymph, and adult, or imago. There is no pupal stage. The nymph resembles the adult but lacks wings and functional reproductive organs.
Insecticide – Chemical substance used for killing insects.
Instar – Name for the stages between molts.
Invertebrates – Organisms with no backbones, such as insects, crustaceans, and mollusks.
Iridescent – Displaying the colors of a rainbow in shifting hues and patterns, as soap bubbles.
Larva – First stage of some insects after leaving the egg. It is an immature form that is unlike the adult and must undergo metamorphosis. Caterpillars and grubs are larva.
Leaf litter – Partially decomposed leaves, twigs and other plant matter that has recently fallen and covers the ground.
Leaf miner – Insect that spends part of its life in the layers of a leaf. As it feeds it bores or tunnels mines which also provide protection.
Leaf roller – Insect that curls part of leaf around its body for protection during an immature stage.
Lymph – Clear liquid inside the body that bathes the cells with water and nutrients.
Mammal – Member of the class of animals that suckle their young.
Mandible - Jaw.
Mechanical control – Method of controlling insects, such as using oil to block the spiracles so an insect cannot breathe.
Metamorphosis – Change in the form of the body during development. For example, the transformation of a caterpillar into a butterfly or a tadpole into a frog.
Mimicry – Copying the shape of another animal or some inanimate object such as a stick.
Molting – Shedding an exoskeleton so an insect can grow.
Naiad - Juvenile form of dragonfly, damselfly, or mayfly.
Nymph – Young insect that resembles its parents in form while undergoing incomplete metamorphosis.
Nocturnal – Mainly active during the night time, resting mostly in the daytime.
Occellus – Simple eye.
Ommatidia – Tiny light sensitive parts of a compound eye.
Omnivorous – Feeding on both plants and animal flesh.
Organic matter – Material that is made of decaying plants and animals.
Ovipositor – External female reproductive organ used to lay eggs.
Parasite – Organism that lives in or on another organism (host) for a portion of its life but does not kill it.
Parasitoid – Insect that lives in another organism and kills it during its development.
Pathogens – Organisms that cause disease.
Pediculosis – Infestation with lice.
Pedipalps - Two jointed “feelers” on a spider’s face. They look like an extra pair of legs, but function like arms for holding. They act like antennae, helping the spider sense objects.
Pheromone – Chemical that sends information to members of the same species.
Predator – Animal that kills other animals for food.
Pronotum – Part of the thorax just behind the head above the elytra.
Protozoan – One-celled microscopic animal.
Pupa – Often wrapped in a cocoon; follows the larval stage in an insect's development.
Resilin – Elastic protein in a flea leg that stores energy and releases it in bursts so the flea can hop.
Salivary glands – Glands in the mouth that make a liquid that helps digest food.
Scavenger – Organism that consumes dead material.
Scutellum – Shieldlike bony plate or scale on the thorax of some insects.
Simple (incomplete) metamorphosis – Insect changes to an adult in only three main growth stages--egg, nymph, adult. No larval or pupal stage. No “resting” stage before adult emerges.
Species - One of the ranks used to classify organisms. Organisms which are very similar to each other can be from the same species.
Spinnerets – Web producing organs.
Spiracle – Opening through the exoskeleton for the passage of water or air for breathing.
Stridulation – Sound produced by action of thick, toothed vein on scraper of a cricket's wing.
Subimago – First winged stage of mayfly.
Superorganism - Colony of individual animals who practice division of labor, communication, and self-organization. The result is a highly connected community that functions as a single organism.
Surface tension – Tendency of water molecules to cling to each other creating a thin film on the surface.
Tarsus – Last (fifth) segment of an insect’s leg.
Tibia – Fourth segment of an insect’s leg between the femur and tarsus.
Tibiae - Plural of tibia.
Thorax – Middle section of the body in between the head and the abdomen.
Toxic – Poisonous.
Trachea – Airway for breathing air also called the “windpipe”.
Tracheal system – Series of tubes that carry oxygen to cells in an insect’s body.
Trochanter – Second segment of an insect’s leg.
True fly – Belongs to the Order Diptera; has only one pair of wings.
Tubercle – Small rounded projection or swelling.
Tympanum – Hearing organ on the inside of a cricket's leg.
Venomous – Delivering or injecting poison.
Vertebrates – Animals with backbones, such as reptiles, amphibians, birds, and mammals.
Wingpad – Immature form of an insect’s wing, unable to produce flight.
Dasheisky, H. S. (1994). Entomology, high-school science fair experiments. Blue Ridge Summit, PA: Tab Books.
Hillyard, P. (1994). The book of the spider. New York, NY: Random House.
Preston-Mafham, K. (1984). Spiders of the world. New York, NY: Facts on File Publications.