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Insect Identification Key
Order Diplura: the two-pronged bristletails

A bristletail
Two-pronged bristletails have two tail-like cerci. In this particular species, the cerci are long and thread-like. This specimen also clearly shows the long, beaded antennae that are characteristic of this order. Photo credit: Mvuijlst at en.wikipedia.
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Based on your answers to the questions, you have identified your insect as being in the class Diplura!

Members of this class include: two-pronged bristletails.

Etymology: Diplura comes from the Greek words diplo, which means two, and ura, which means tail. Diplura, therefore, means “two-tails,” which is a reference to the two tail-like cerci characteristic of these organisms.

General characteristics:
• small – most are 2-5 mm, or 0.08-0.2 inches long, but a few species can reach 5 cm or 2 inches in length
• soft, pale-colored body
• eyeless
• wingless
• long antennae that look like strings of beads
• two cerci, which may be long and thread-like, or short and pincer-like
direct development (nymphs and adults nearly indistinguishable)

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Number of species worldwide: about 800

Kingdom Animalia
   Phylum Arthropoda
      Subphylum Hexapoda
         Class Diplura (see classification note below)

For a list of all of the orders in this key, click here: List of Orders.

Classification note: The diplurans were once considered insects (in the class Insecta), but were removed once scientists determined that they, Protura and Collembola were not in the evolutionary lineage of insects. In other words, these three groups did not give rise to modern-day insects. Scientists are still working out the tree of life for Diplura, Protura and Collembola. Most authorities place them into their own classes: Class Protura, Class Diplura and Class Collembola. Some authorities, however, group them together under one class called Class Entognatha and list them as orders, and still others put only Protura and Collembola in the Class Entognatha and place Diplura in its own class: Class Diplura.

Oops! If this doesn't appear to be the order for your insect, go back through the key and look more carefully at your insect while answering the questions again. Your perseverance will reward you!

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Photos at the top of this website are (from left to right): potato beetle (Leptinotarsa decemlineata) — photo credit: Scott Bauer, U.S. Department of Agriculture; ebony jewelwing (Calopteryx maculata)— photo credit: U.S. Fish and Wildlife Service; sweat bee (Agapostemon splendens) — photo credit: Natalie Allen and Stephanie Kolski, U.S. Geological Survey; preying mantis, monarch butterfly (Danaus plexippus), hellgrammite (aka toe biter) larva and eyed click beetle (Alaus oculatus) — photo credit: Leslie Mertz; Halloween pennant (Celithemis eponina) — photo credit: Kay Meng, U.S. Fish and Wildlife Service.

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