tion in that it is a water- breather and has six pairs of legs.) Examples, scor- 

 pions, spiders, daddy longlegs, tarantula, mites, ticks (see illustrations, pp. 617 

 and 561). 



CLASS 4 INSECTS ("cut in"). Body segmented; three distinct parts — 

 head, thorax, and abdomen; three pairs of legs; usually two pairs of wings; 

 antennae; compound eyes; breathe air through numerous branching tubes 

 called tracheae; metamorphosis of some forms includes tgg, larva, pupa, and 

 adult stages (see illustrations, pp. 352, 353 and 655). This important class 

 comprises more than half the animal species. The chief orders are as follows: 



Order 1 Diptera ("two-wings"). Hind pair of wings reduced to tiny 

 knobs, or balancers; complete metamorphosis; sucking or piercing 

 mouth. Examples, mosquitoes (see illustration, p. 623), gnats, midges, 

 houseflies, stable flies, botflies, warbles, fruit flies (see illustrations, 

 pp. 489, 490, and 513). 



Order 2 Lepidoptera ("scale- wings"). Rigid membranous wings 

 covered with minute scales; complete metamorphosis; sucking pro- 

 boscis. Examples, all butterflies and moths (see illustrations, pp. 180, 

 263, 353, 391 and 655). 



Order 3 Hymenoptera ("membrane- wings"). Complete metamor- 

 phosis; biting or sucking mouth. Examples, wasps, hornets, bees, 

 ichneumons, ants (see illustrations, pp. 352 and 410). 



Order 4 Coleoptera ("sheath- wings"). The front wing a hard pro- 

 tective cover; complete metamorphosis; mostly with biting mouth. 

 Examples, beetles, weevils, fireflies, ladybird, June-bug (see illustra- 

 tions, pp. 352, 596 and 655). 



Order 5 Heteroptera ("unlike- wings"). Front pair of wings 

 usually leathery at base and membranous near tip; incomplete meta- 

 morphosis; sucking mouths. Examples, all true bugs, squash-bug, 

 water- bug, bed-bug. 



Order 6 Homoptera ("like- wings"). Usually have two pairs of wings 

 with front pair uniform in texture throughout; incomplete metamor- 

 phosis; sucking mouths. Examples, cicadas, plant lice, scales, hoppers, 

 white flies. 



Order 7 Orthoptera ("straight- wings"). Wings lying parallel with 

 body or folding lengthwise; incomplete metamorphosis; biting 

 mouth. Examples, locusts, crickets, walking sticks, katydids, cock- 

 roaches, mantis. 



694 



