Structure and classification of insects . egreeof heat more rapidly pass into the perfect states and itcan also be greatly retarded by being placed in a lowtemperature. But some pupse have a periodic time for passing intothe perfect state, quite independent of the circumstancesof temperature. Such, for example, are the Ephemerae,which, in the proper season of the year, mature at be-tween eight and ten in the evening, regardless of cold orrain, and certain species of silk worm and hawkmoths,which break forth from the pupa at sunrise. The sex of the pupae may be distinguished chiefly bythe male
Structure and classification of insects . egreeof heat more rapidly pass into the perfect states and itcan also be greatly retarded by being placed in a lowtemperature. But some pupse have a periodic time for passing intothe perfect state, quite independent of the circumstancesof temperature. Such, for example, are the Ephemerae,which, in the proper season of the year, mature at be-tween eight and ten in the evening, regardless of cold orrain, and certain species of silk worm and hawkmoths,which break forth from the pupa at sunrise. The sex of the pupae may be distinguished chiefly bythe male being smaller than the female, and often by theevident organs of oviposition of the female doubled up onthe abdomen, as the tongue sometimes is on the thorax. Incomplete pupae often continue their powers of motion S2 THE PUPA. througli tlie entire state, effected by the movement of tlieabdominal segments solely, but coarctate pupse, or chrysa-lids, are incapable of even the sligbest motion, and ex-hibit no symptoms whatever of We would next consider the extrication of the perfectinsect from the -pui^Si case, or the puparium, and from thecocoon. This may be considered under two heads, viz: 1st, Thestate or condition of the pupa when about to moult, and2d, The means by which the insect frees itself from thepupa case and from the cocoon. At the period of change the color of the pupa is apt tobecome more dull and transparent, often to such a degreethat the motions of the insect within may be distinguished. While the pupa case, however, loses its brilliancy, thebeauties of the insect within become more apparent. THE PUPA. 33
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectinsects, bookyear1872
