KINDS OF ANIMALS 487 



i. Aptera (" without wings "'). The most primitive insects now living. 

 (Examples. Silverfish and springtail.) 



2. Orthoptera (" straight-winged "). Wings lying parallel with body 



or folding lengthwise ; incomplete metamorphosis ; biting 

 mouth. {Examples. Locusts, crickets, walking sticks, katy- 

 dids, cockroaches, mantis.) 



3. Neuroptera (" netted-veined wings"). A large group broken up into 



several orders by entomologists ; complete metamorphosis ; 

 biting mouth. [Examples. Mayflies, dragonflies, termites.) 



4. Hemiptera (" half-wings "). Basal part of wings often thickened 



and without distinct veining ; incomplete metamorphosis; suck- 

 ing mouths. All true bugs. {ExatHples. Squash-bug, bed-bug, 

 water-bug, plant lice, scales, lice, cicada.) 



5. Coleoptera (" sheath-wings "). The front wing a hard protective 



cover ; complete metamorphosis ; mostly with biting mouth. 

 {Exa7}iples. Beetles, weevils, fireflies, ladybird, June-bug.) 



6. Lepidoptera (" scale-wings '"). Rigid membranous wings covered with 



minute scales ; complete metamorphosis ; sucking proboscis. 

 {Examples. All moths and butterflies.) 



7. Diptera (" two-wings "). Hind wings reduced to tiny knobs, or 



" balancers " ; complete metamorphosis ; sucking or piercing 

 mouth. [Examples. Mosquitoes, gnats, midges, house flies, 

 stable flies, botflies, warbles, fruit flies. 



8. Siphonaptera (" tube-wingless "). Sucking mouth, wings reduced ; 



complete metamorphosis ; parasitic on birds and mammals. 

 [Examples. Fleas of all kinds.) 



9. Hymenoptera (" membrane wings '"). Complete metamorphosis ; 



biting or sucking mouth. (Examples. Wasps, hornets, bees, 

 ichneumons, ants.) 



507. The families of primates. The order Primates is no 

 doubt of great importance in the world, since it includes the 

 human species. From a zoological point of view, however, it 

 cannot be considered the highest group of animals, since in 

 many respects the skeleton, the muscles, and the teeth of 

 man and the apes are not so highly specialized as are the 

 corresponding organs of such animals as the whales or the 

 elephants, for example. Nevertheless, the remarkable develop- 

 ment of the nervous system among the primates entitles them 

 to a distinctive place in the animal world. 



