Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada

Class Insecta - Insects

Anicla infecta another really tiny wasp - not sure if same species as another I submitted moments ago - Halictus confusus - female Cuerna? - Cuerna arida Coleoptera - Scirtes tibialis Andrena female - Andrena Cerceris Fly ID? Oulema arizonae? - Oulema arizonae
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Synonyms and other taxonomic changes
arrangement of major extant taxa based on molecular data in (1)
Explanation of Names
Insecta Linnaeus 1758
Latin insectum, pl. insecta "cut into, cut up" (refers to body segmentation), a literal translation of Greek entomos (εντομος)
~30 extant + a dozen extinct orders, up to 1000 families, and well over a million described species
In our area (US & Canada): 28 orders, over 600 families, ca. 12,500 genera, and >86,000 spp.(2)(3)
Three pairs of legs
Three body parts: headthoraxabdomen
typically two pair of wings; some groups have one pair or none
One pair of antennae
See Glossary for terminology
aquatic marine forms conspicuously absent
Life Cycle
Hemimetabolous insects (e.g., dragonflies, mayflies, true bugs, grasshoppers) undergo gradual, or incomplete, metamorphosis. Immature stages (usually called nymphs) go through a series of molts, gradually assuming an adult form. Since the wings develop on the outside of the body, these groups are called exopterygotes. Some orders have immature stages that are aquatic. These possess specialized structures for aquatic life, such as gills, and are called naiads, or larvae.
Holometabolous insects (Endopterygota or Holometabola) have a four-stage life cycle: egg, larva, pupa, and adult (imago).
Neuroptera - Antlions, Lacewings and Allies
Coleoptera - Beetles
Hymenoptera - Ants, Bees, Wasps and Sawflies
Trichoptera - Caddisflies
Lepidoptera - Butterflies and Moths
Mecoptera - Scorpionflies, Hangingflies and Allies
Diptera - Flies
Strepsiptera - Twisted-winged Insects
Siphonaptera - Fleas
Print References
Stork N.E. (2018) How many species of insects and other terrestrial arthropods are there on Earth? Ann. Rev. Entomol. 63: 31‒45. Full text
Internet References
Works Cited
1.Phylogenomics resolves the timing and pattern of insect evolution
Bernhard Misof et al. 2014. Science Vol. 346, 763.
2.American Insects: A Handbook of the Insects of America North of Mexico
Ross H. Arnett. 2000. CRC Press.
3.Evolution of the Insects
David Grimaldi and Michael S. Engel. 2005.
4.How to Know the Immature Insects
Hung-Fu Chu, Laurence K Cutkomp. 1992. Wm. C. Brown Publishers.