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morphosis, and the third includes insects that undergo a complete metamorphosis. Primitive Wingless Insects The four most primitive orders of insects are wingless and their small size and retiring habits make them easy to overlook. Order Thysanura. Bristletails, silverfish and allies are in this order of insects whose bodies are covered with scales. They bear long antennae, and have short legs and three long bristles or cerci at the tail end. Order Diplura. These soft-bodied insects have two cerci at the tail end. They are sometimes called twotailed bristletails. Order Collembola. These tiny, squat insects are able to leap by means of a sprung lever at their tail end, and are commonly called springtails. Order Protura. There is no common English name for these minute, soil-dwelling insects that lack eyes and antennae.

segments and contains many of the insect’s vital internal organs. Entomologists—scientists who study insects—place them in a subdivision of the arthropods called a class. Within the whole class, insects with characteristics in common are further distinguished by orders. All orders, except the most primi- tive, are familiar to naturalists and have common names. The many orders of insects fall into three categories. The insects of the first cate- gory do not undergo any kind of metamor- phosis, are wingless, and are considered primitive. Only four orders fall into this category. The remaining orders comprise mostly insects whose adults have wings and some insects whose adults have lost their wings as a result of evolution. These winged orders fit into the second and third categories. The second comprises insects whose life cycles involve only partial meta-

In terms of appearance, weevils (Curculionidae) are among the most extraordinary of all beetles. The blue coloration of this painted weevil only adds to the creature’s visual impact on the observer.

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