Annual report of the Fruit Growers' Association of Ontario, 1904 . Srif^aCal I ?ochea Fic. 22. Respiratory S3stem of Grasshopper (after Hyatt). fact, most insects pass through a more or less marked change during theirlives. This is known as Metamorphosis, which is said to be complete (), when the insect passes through a stage of almost total rest, takes no food,and moves but little; and incomplete (Fig 24), when the insect does not passthrough a stage of rest, but feeds and changes its form gradually with everymoult, becoming more and more like the adult. As insects grow they castoff the
Annual report of the Fruit Growers' Association of Ontario, 1904 . Srif^aCal I ?ochea Fic. 22. Respiratory S3stem of Grasshopper (after Hyatt). fact, most insects pass through a more or less marked change during theirlives. This is known as Metamorphosis, which is said to be complete (), when the insect passes through a stage of almost total rest, takes no food,and moves but little; and incomplete (Fig 24), when the insect does not passthrough a stage of rest, but feeds and changes its form gradually with everymoult, becoming more and more like the adult. As insects grow they castoff their old skin at intervals. The new skin is soft and elastic, but as itgets older, it becomes hard and inelastic. This is stripped off and replaced. Fig. 23. Complete metamorphosis ; a caterpillar ;b chrysalis in a cocoon ; c moth. by a new one. By this moulting, growth is not interfered with. Amongthese insects which undergo complete metamorphosis are : Butterflies, moths,beetles, bees and wasps and flies. The different stages are known as egg, larva,pupa, and adult. The larval stage of insects is the most important onefrom an economic standpoint, for it is the feeding stage, and it is then thatvegetation is injured. The larvse of butterflies and moths are known ascaterpillars (Fig. 21), and have usually 8 pairs of legs, sometimes only 5pairs; those of saw-flies have usually 10 pairs of legs. 1904 ENTOMOLOGICAL SOCIETY. 101 Grubs are tlie larvae of beetles (Fig. 25), and liave commonly only threepairs of legs. Maggots are the larvse of flies (Fig. 26), bees and wasps, andare footless. 4 U-. \i m i J4 ?> y - \ Fig. 24. Incomplete metamorphosis of a Cockroach ; a, 6,c, d, young larvae ; e, f, h, winged adults ; g eggmass,magni
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