INSECT METAMORPHOSIS 



it is provided with food by the parents. Some of the 

 wasps store paralyzed insects in the cells of the nest for 

 the young to feed on; the bees give their young a diet of 

 honey and pollen, with an admixture of a secretion from a 

 pair of glands in their own bodies. The grubs have noth- 

 ing to do but to eat; they have no legs, eyes, or antennae; 

 each is a mere body with a mouth and a stomach. The 

 adult bees consume much honey, which, like its con- 

 stituent, nectar, is an energy-forming food; but they also 

 eat a considerable quantity of protein-containing pollen. 

 Yet it is a great advantage to the bees in their social life 

 to have their young in the form of helpless grubs that 

 must stay in their cells until full-grown, when, by a quick 

 transformation, they can take on the adult form and be- 

 come at once responsible members of the community. Any 

 parents distracted by the incorrigibilities of their offspring 

 in the adolescent stage can appreciate this. 



The young mosquito (Fig. 174 D, E) lives in the water, 

 where it obtains its food, which consists of minute par- 

 ticles of organic matter. Some species feed at the surface, 

 others under the surface or at the bottom of the water. 

 The young mosquito is legless and its only means of pro- 

 gression through the water is by a wiggling movement 

 of the soft cylindrical body. It spends much of its time, 

 however, just beneath the surface, from which it hangs 

 suspended by a tube that projects from near the rear end 

 of the body. The tip of the tube just barely emerges 

 above the water surface, where a circlet of small flaps 

 spread out flat from its margin serves to keep the creature 

 afloat. But the tube is primarily a respiratory device, for 

 the two principal trunks of the tracheal system open at its 

 end and thus allow the insect to breathe while its body is 

 submerged. 



The adult mosquito (Fig. 174 A), as everybody knows, is 

 a winged insect, the females of which feed on the blood of 

 animals and must go after their victims by use of their 

 wings. It is clear, therefore, that it would be quite im- 



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