Kingdom - Animalia

Phylum - Arthropoda

Subphylum - Hexapoda

Class - Insecta





Insects have:

  • three main body parts - head, thorax, abdomen.
  • three pairs of legs - 6 total.
  • one pair of antennae.
  • a hard exoskeleton.


Almost all insects undergo some form of metamorphosis - a transformation from an immature life stage to an adult form.


Basic Insect Taxonomy



Winged Insects




Wingless primitive insects

- three long caudal (tail) filaments
- no wings
- no metamorphosis

(formerly Thysanura)


- single joint attachment to head
- "ancient jaw"
- two connected, enlarged, compound eyes
- abdominal muscles allow jumping
- wingless
- three caudal filaments



Non-folded Wing

- incomplete metamorphosis
- nymphs/naiads look like small wingless adults

dragonflies, damselflies




Folded Wing Insects


Hemipteroid Assemblage

- gradual or simple metamorphosis
- lack cerci
- have mouthparts for sucking

lice & booklice


true bugs












- complete metamorphosis.
- wings develop during pupal stage.
- no food is consumed during pupal stage.


Entomology is a branch of Zoology that deals with insects. In other words, insects are animals. They differ from other animals in that they have three body parts, a head, thorax, and abdomen, on which are found three pairs of jointed legs. The insects have external mouth parts and are covered by a tough, waterproof exoskeleton. Most have wings.

In the entire world, there are about one and a half million animal species described. Of this number, about one million are insects.

Insects are bees, beetles, and butterflies. They are froghoppers, firebrats, and flies. They are also midges, moths, and mayflies. And there are more, so many more. Insects can be found in every type of habitat. From the Arctic to the Antarctic, treehole to tree canopy they occupy every land niche.

They are essential to our well-being. Insects are plant pollinators, scavengers eating decaying debris, a source of medicine, recyclers of nutrients, a source of food for other animals and even some plants. Many are aesthetically pleasing and all are a source of wonder in their architecture and engineering feats.

Entomologists continue to gather facts about these animals. Entomologists work in areas such as beekeeping; insect diseases; pest control; the effects of pesticides on insects, birds, and mammals; and classification and teaching; and in such areas of biological research as life history, ecology, behavior, physiology, and morphology.


Insect-related biodiversity information

INHS Insect Collections

Some past articles published in INHS Reports:

Soybean Aphids and the Search for Natural Enemies. Winter 2002

The Endangered Hine's Emerald Dragonfly. Autumn 2001

Species Spotlight: Fireflies. Autumn 2001

The Spread of the Gypsy Moth. Summer 2001

Changes in the Pollinator Guild of a Prairie Species in the Past 70 Years. Summer 2001

Illinois River Valley Ticks. Fall 2000

Plant Stress--Its Relationship to Arthropod Pests in Urban Landscapes. March-April 2000

Insect Invaders Infest Chicago Trees . March-April 2000

Influence of Intercropping and Trap Cropping on Diamondback Moth and Its Natural Enemies. January-February 2000

Species Spotlight: Monarch Butterfly. September-October 1999

Monitoring the Spread of Western Corn Rootworm Beetles Infesting Illinois Soybean Fields. January-February 1999

"Clean Sets in Clean Ground" -- Successful Management of the Imported Crucifer Weevil on Horseradish. November-December 1998

Mosquito Marauder: Asian tiger mosquito. November-December 1998

Good Beetle, Bad Plant. November-December 1998

The Beetle That Tried to Steal Christmas. November-December 1998

Species Spotlight: Walking Stick. July-August 1998

Western Corn Rootworm Flight Activity in Soybeans. March-April 1998

Lyme Disease Alert. March-April 1998

Insects and Fire: Too Much of a Good Thing?. January-February 1998

White Grub Management Options in Turfgrass. January-February 1998

Mayflies, Stoneflies, and Caddisflies Help Researchers Track Water Quality. November-December 1997

Gypsy Moth in the Chicago Area: Disaster for All of Moderate Problem for Some?. November-December 1997

Complex Life-cycle Puzzles. September-October 1997

Forage Crops (Integrated Pest Management). March-April 1997

European Corn Borer Management: Past and Present. January-February 1997

Microbial Larvicides in Mosquito Control. November-December 1996

Using Biological Control to Lose Loosestrife in Illinois. September-October 1996

Using Natural Enemies for Pest Control. July-August 1996

Species Spotlight: Cecropia Moth. July-August 1996

Rootworm Problems in First-year Corn: an Update. May-June 1996

Children in Biological Control Research. March-April 1996

Human Monocytic Ehrlichiosis. January-February 1996

Identifying Specimens On-line. November-December 1995

Aphids and Disease Spread in Crops. November-December 1995

Pearly Eyes in Illinois. September-October 1995

Species Spotlight: Green Tiger Beetles. July-August 1995

New Version of an Old Classic. July-August 1995

Helicopter Captures Russian Wheat Aphids. May-June 1995

Western Corn Rootworm Problems. May-June 1995

Species Spotlight: Millipedes. May-June 1995

North Central Regional Committee on the Biological Control of Arthropods. March-April 1995

Habitat Partitioning by Therevids at Sand Ridge State Forest. January-February 1995

Corn Rootworm Injury: Reducing Prophylactic Soil Insecticide Treatments. January-February 1995


For more information, see the INHS Insect Collection Page