STRUCTURE AND DEVELOPMENT OF INSECTS 



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not all of these parts are always recognizable, the legs and mouth- 

 parts being sometimes lacking. Gradually the adult insect 

 develops, and at last the pupal skin is broken open and the airy 



Fia. 16. Incomplete metamorphosis of a bug (Brachymena 4-pustulata) : 

 a, eggs; 6, adult bug; c, different stages of young bugs or nymphs. 



butterfly emerges to enjoy a short life and perpetuate the species. 

 Such a series of transformations is that commonly found among 

 butterflies and moths (Lepidopterd) , beetles (Coleoptera) , flies 

 (Diptera), and bees (Hymenoptera) , and is known as a complete 

 metamorphosis. All of these insects normally pass through 

 four stages, egg, larva, pupa, and adult. 



Incomplete Metamorphosis. In contrast to this mode of 

 development is that of the grasshoppers (Orthoptera) , bugs 

 (Hemiptera), and some other insects. As already stated, these 

 are much like the adult upon emerging from the egg. With 



