Insect Identification

- You'll need good reference material -

Summary: In order to do even basic insect identification yourself you'll need a few inexpensive tools plus good reference books, and a little practice. Common household insect pests are listed with brief descriptions.

Jack DeAngelis, PhD
OSU Ext. Entomologist (ret.)

At its core the 'Bugs website is about insect identification. Our aim is to make you better at identifying and understanding insects in the hope that you will be less likely to try to control what are often harmless, or even beneficial, insects and spiders.

There are many excellent guidebooks available that can help you identify an unknown specimen. The big advance in recent years is that you now have access to high quality images online. Be cautious however because occasionally images you find online are misidentified. Be sure to judge the overall reliability of a site before depending on the identification and check at least two different sites if possible.

Using printed and online resources makes insect identification possible even for novices. With a little practice you'll be able to id the major groups yourself. With practice you'll be able to tell the major insect orders apart (beetles, ants, flies, true bugs, moths, and so forth) as well as distinguish spiders from insects.

anatomy of a flea

External anatomy of a flea. Original drawing from CDC Pictorial Keys To Arthropods, Reptiles, Birds and Mammals of Public Health Significance. 1967.

The most common insect id questions we get

The most common bug id requests we get are listed below along with a brief description.

  • Carpet Beetles - small, slow moving beetles that infest dry foods and fabrics.
  • Springtails/Collembola - tiny insects ranging in color from light to dark, and even bright colors, that enter homes often following heavy rains.
  • Bed Bugs - small, brown, "football"-shaped insects associated with bedding or furniture, can cause bites.
  • Cockroaches - small to medium-size, brown to black insects with long antennae that often scurry when exposed.
  • House Centipedes - medium-size bugs with multiple, long, thin legs.
  • Fungus Gnats - tiny dark flies, often found indoors around potted plants.
  • Spiders - except for common species, spiders are very difficult to identify.
  • Also, take a look at this list of some of the most Common Household Pests.

Arthropod classification

The word "arthropod" means jointed leg or foot. It includes the crustaceans - crabs and their relatives - and the insects, and their relatives like spiders, ticks, scorpions, centipedes, and millipedes. The Class Insecta, or Hexapoda, includes the insects, and their close relatives, while the Class Arachnida includes the spiders, mites, ticks, scorpions, and some other minor groups. There are well over 20 insect Orders alone. The major insect groups that homeowners will most often encounter are true bugs (Hemiptera), aphids and scales (Homoptera), beetles (Coleoptera), ants, bees, and wasps (Hymenoptera), mosquitoes and other flies (Diptera), and, moths and butterflies (Lepidoptera).

Make a collection

The best way to learn insect identification is to make a reference, or synoptic, collection (see Related Articles below). Start slowly with a few specimens you find in your home or garden and use guidebooks, online pictures and "keys" to identify these as best you can. If you have access to a university you'll likely find people there willing to help as well.

Get a field guide

The easiest way to start identifying insects around the home is with a field guide to your local insects and related arthropods. Field guides are usually specific to a particular region but regions can be large such as "North America" or more specific such as "Rocky Mountains". The smaller the region the more specific will be the included species. If you are really serious you'll also need a general entomology textbook to learn the basics of anatomy, classification and life histories of insects. Finally you'll need a good hand lens (see Purchasing and Using a Hand Lens) for getting a close-up view of small specimens.

This DK Smithsonian Handbook is an excellent general guide to Insect Identification (available through Amazon, our Affiliate):

Related Articles

Collecting & Preserving Insects - Part 1, Part 2

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