THE CATERPILLAR AND THE MOTH 



is likely to be unable to accomplish its transformation, or 

 it will produce a dwarfed or an imperfect adult. 



How the Caterpillar Becomes a Moth 



A short time before the caterpillar is ready to spin its 

 cocoon, it ceases feeding. Its body, as we have just 

 learned, contains now an abundance of energy-giving sub- 

 stances stored in the cells of its fat tissue. When the work 

 of constructing the cocoon is started, the alimentary canal 

 is devoid of food material, the crop is contracted to a 

 narrow cylinder, and the stomach is shrunken and flabby. 

 The stomach, however, contains a mass of soft, orange- 

 brown substance which, when examined under the micro- 

 scope, is found to consist, not of plant tissue, but of animal 

 cells; it is, in fact, the cellular lining of the caterpillar's 

 stomach which has already been cast off into the cavity 

 of the stomach. The latter is now provided with a new 

 cell wall. The shedding of the old stomach wall marks the 

 first stage in the dismantling of the caterpillar; it is the 

 beginning of the pupal metamorphosis which will convert 

 the caterpillar into the moth. The new stomach wall will 

 first digest and absorb the debris of the old, in order to 

 conserve its proteid materials for the constructive work 

 of the pupa, and it will then itself become transformed 

 into the stomach of the moth. 



After the caterpillar has shut itself into the cocoon, its 

 lite as a caterpillar is almost ended. Its external appear- 

 ance is already much altered by the contraction of the 

 body and the loss of the hairy covering, and during the 

 next three or four days a further characteristic change of 

 form takes place. As the body continues to shorten, the 

 first three segments become crowded together; but the 

 abdomen swells out, while the abdominal legs are re- 

 tracted until they all but disappear. The creature is now 

 (Fig. 159 B) only half the length of the active caterpillar 

 (A), and it would scarcely be recognized as the same in- 

 dividual that so recently spun itself into the cocoon. 



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