Today our post was inspired by the picture book A World of Bugs (Comparing Bugs: Acorn Read-Aloud) by Charlotte Guillain.

Way back when I started this blog, I purposely chose the title “Bug of the Week” for the long-running Wednesday feature because I knew I would want to include spiders, pill bugs, and other creepy crawlies, as well as insects.  A World of Bugs shows children the range of arthropods and other invertebrates that are often called “bugs.” It tells what their features are, how they grow, where they live, and how they move. It is filled with huge, full color photographs that are very attractive. On the last page, the book also has some suggestions for activities to do before and after reading the book.

Identification of insects and their relatives requires careful observation of their anatomy.

Insects are part of the phylum of animals called Arthropoda.  All arthropods have:

  • supporting skeleton on the outside, called an exoskeleton
  • bi-lateral symmetry, which means if you draw a line down the center the two sides will be symmetrical
  • jointed appendages
  • segmented bodies
  • specialized appendages, like antennae

The major arthropod classes can be separated by comparing their number of body regions, legs, and antennae.

Activity 1. Compare various creatures to discover features using live arthropods to observe, pictures and rubber or plastic models to explore. Give the children free explore time at first, and then start to encourage them to observe the following features:

Arachnids are the spiders, ticks, mites, scorpions and their relatives

  • Have 8 legs
  • Have 2 body regions, the cephalothorax (literally head-thorax), and abdomen

Spiders have 6 or 8 eyes at the front of the cephalothorax. Spiders’ mouthparts are called chelicerae and typically end in a fang. Around the mouth are the pedipalps.

For detailed information about spider anatomy, see Invertebrate Anatomy Online, the Garden Spider.


The Isopods, which are called pillbugs, roly-polies, or wood lice, and other common names, have:

  • 12 legs
  • 2 antennae (one pair small)

Pill bug activities for kids

Centipedes and millipedes

  • Many legs per segment
  • Many segments
  • One pair of antennae

Millipedes have 2 pairs of legs per segment.

Centipedes have one pair of legs per segment. (Photograph from Wikimedia).

Insects have:

  • Three body parts:  head, thorax and abdomen
  • Six legs
  • One pair antennae
  • Many adults have wings, but not all

Next time we will discuss how to recognize the major groups of insects, the orders.

A World of Bugs by Charlotte Guillain

Reading level: Ages 4-8
Paperback: 24 pages
Publisher: Heinemann-Raintree (August 1, 2011)
ISBN-10: 1432955063
ISBN-13: 978-1432955069

Book was provided by publisher for review purposes.