TRANSFORMATION OF ANIMALS. 1G1 



only. They walk in the first, and fly in the second. Thus 

 their only metamorphosis consists in the addition of wings, 

 the growth and expansion of which are performed without any 

 considerable alteration in the figure of their bodies. 



There is not a law established among organized bodies 

 which seems to be so universal, as that all of them grow or 

 augment in size, after birth, till they arrive at maturity. If a 

 hen were to bring forth an egg as large as her own body, and 

 if this egg, when hatched, were to produce a bird of equal 

 dimensions with either of the parents, it would be considered 

 as a miracle. But the spider-fly, so denominated from its 

 figure, affords an example of a similar prodigy. This vfly ac- 

 tually lays an egg, from which a new fly is hatched that is as 

 large and as perfect as its mother. This egg is roundish, is 

 at first white, and afterwards assumes a shining black color. 

 Upon a more accurate examination, however, this production 

 is found to be an egg only in appearance. When the envelope 

 is removed, instead of a gelatinous substance, the new insect, 

 furnished with all its members, is discovered. But this dis- 

 covery does not render the fact the less wonderful. All 

 winged insects undergo their different transformations after 

 being expelled from the bodies of their mothers, a-nd receive 

 great augmentation of size before their metamorphosis into 

 the nymph or chrysalis state, after which their growth stops. 

 But the spider-fly affords an instance of an insect transformed 

 within its mother, and which grows no more after it escapes 

 from its envelope. 



The worm, from which the tipula or crane-fly is produced, 

 is perfectly smooth. Immediately before its first transforma- 

 tion it retires under ground. After this metamorphosis, the 

 surface of the nymph is furnished with a number of spines. 

 By means of these spines, the nymph, when about to be trans- 

 formed into a fly, raises itself in its hole till the chest of the 

 insect is above ground. The fly then bursts its prison, mounts 

 into the air, and leaves its former covering behind in the earth. 



Many species of flies deposit their eggs in the leaves and 

 different parts of plants. Soon after the egg is inserted into 

 the leaf, a small tubercle begins to appear, which gradually 

 increases in magnitude till the animal is hatched and has 

 passed through its different transformations. These tubercles 

 are known by the name of galls, and are very different in their 

 form, texture, color, and size. Galls of every kind, however, 

 derive their origin from the perforat,ors of insects, which gen- 

 erally belong to the class of flieg. The female fly, by means 

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