238 HOW DO WE CLASSIFY ANIMALS? 



There are a number of orders of insects, but examples of the 

 following orders are the ones most commonly found. 



Order 1. Coleop'tera (sheath wings). Hard outer wings, forming 

 cover for under wings. Biting mouth parts. Complete meta- 

 morphosis. Examples : all beetles and fireflies, etc. 



Order 2. Dip'tera (two wings). Insects with two wings, a few 

 with none. Mouth parts fitted for sucking or piercing. Com- 

 plete metamorphosis. Examples : all flies, mosquitoes, gnats, etc. 

 There are 40,000 described species and it is estimated that there 

 are more than 300,000 as yet undescribed. 



Order 3. Ephemer'ida. Insects having complete metamorphosis 

 and biting mouth parts. They have long setae which project 

 from the end of the abdomen. The adult lives only a day or two, 

 lays eggs, and dies. Examples : the mayflies. 



Order 4. Hemip'tera (half wings) . Sucking mouth parts. Incomplete 

 metamorphosis. Two pairs of wings or none. Examples : 

 chinch bugs and squash bugs. 



Order 5. Homop'tera (similar wings). Two pairs of wings alike, 

 sucking mouth parts, incomplete metamorphosis. Examples : 

 cicadas, plant lice, scale insects. 



Order 6. Hymenop'tera (membrane wings). Four membranous 

 wings. Mouth parts fitted for biting and sucking. Often long 

 ovipositor modified into sting. Complete metamorphosis. Ex- 

 amples : bees, ants, and wasps, gall and ichneumon flies. 



Order 7. Lepidop'tera (scale wings). Four wings, covered with 

 scales. Mouth parts long sucking tube. Complete metamor- 

 phosis. Examples : Moths and butterflies. 



Order 8. Neurop'tera (veined wings). Four membranous wings 

 with many veins. Biting mouth parts. Complete metamor- 

 phosis. Examples : ant lions, dobson flies, etc. 



Order 9. Odon'ata. Complete and incomplete metamorphosis. 

 Biting mouth parts. Adults are expert flyers, have large eyes, 

 live mostly in water. Examples : dragon flies and damsel flies. 



Order 10. Orthop'tera (straight wings). Four wings, front pair 

 straight and leathery. Biting mouth parts. Incomplete meta- 

 morphosis. Examples : grasshoppers, crickets, and cockroaches. 



Order 11. Siphonap'tera (tube; wingless). Largely parasitic. 

 Sucking mouth parts. Wingless. Complete metamorphosis. 

 Examples : fleas. 



Order 12. Trichop'tera (hairy wings) have four hairy wings, rudi- 

 mentary mouth parts, complete metamorphosis. Examples : caddis 



Arachnids (spiders) and myriapods. The body of a spider, like 

 that of the crustaceans, has only two divisions, cephalothorax 

 (head thorax) and abdomen. Spiders have four pairs of walking 

 legs, usually four pairs of simple eyes, and breathe by means of 





