. Elementary entomology. Insects. GROWTH AND TRANSFORMATIONS OF INSECTS 49 the adult insect emerges, with wings soft and limp but expand- ing and hardening in a few hours, when it is ready to seek food and a mate. Thus the stages of growth of those insects having a complete metamorphosis are essentially different from those having the in- complete type, as indicated in the following summary : Incomplete metamorphosis : Egg, Nymph, Adult. Complete metamorphosis : Egg, Larva, Pupa, Adult. An insect never grows after it reaches the adult stage. The little flies which appear on the window in early
. Elementary entomology. Insects. GROWTH AND TRANSFORMATIONS OF INSECTS 49 the adult insect emerges, with wings soft and limp but expand- ing and hardening in a few hours, when it is ready to seek food and a mate. Thus the stages of growth of those insects having a complete metamorphosis are essentially different from those having the in- complete type, as indicated in the following summary : Incomplete metamorphosis : Egg, Nymph, Adult. Complete metamorphosis : Egg, Larva, Pupa, Adult. An insect never grows after it reaches the adult stage. The little flies which appear on the window in early spring are not 'baby" flies and do not grow larger, but are entirely different from other larger species which supersede them later in the season. The life histories of insects are as diverse as are the species, no two being quite alike. To study and carefully deter- mine the time, place, and manner of the trans- formations is one of the most important duties of the economic ento- mologist, for by ascer- taining them the means of control of injurious species are often dis- covered. Many insects may thus be controlled by simply changing gen- eral farm methods, such as the rotation of crops, the time of plowing, etc., which result in the prevention or miti- gation of the pest; or a knowledge of the feeding habits may indi- cate the most promising means of attack, and successful methods may be determined by subsequent FIG. 61. Chrysalis of black swallow-tailed butterfly (Papilio polyxenes] Showing attachment of tip of abdomen to mass of silk threads which have become torn from around the stem, and the silken loop which supports the thorax. (Photograph by Weed). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Sanderson, Dwight, 1878-1944; Jackson, C. F. (Cicero Floyd), b. 1882. Boston, New Yo
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