CHAPTER XXIV 



LIVING EXAMPLES OF THE GEOLOGICAL PAST 



STRANGE as it may seem, the most ancient types of insects 

 are still represented alive, in the world today. Unlike the 

 ancient men and mammals of our planet, whose scanty his- 

 tory comes to us through occasional beds of fossil remains, 

 insects provide us, through those which live today, with an actual 

 glimpse into the great geological past. 



Some of the creatures have undergone little change during 

 millions of years. They are today almost what their ancestors were 

 in those past ages, ancestors who roamed the prehistoric fields and 

 forests, now buried deep in the crust of the earth. 



That these insects still exist, almost unchanged, still primitive in 

 their structure, shows that Nature does not always do away with her 

 early experiments. She does not cause them all to become extinct 

 in favor of more modern ones. 



These primitive insects which still inhabit the world, are known 

 scientifically as Aptera, an order which includes two suborders, the 

 Thysanura and Collembola, commonly known as Bristle-tails and 

 Spring-tails. 



Aptera today are the most widely distributed of all insects. They 

 are found in Europe, the Faroe Islands, Chile, Alaska, Joseph 

 Land, the Sandwich Islands, the South Orkneys, Graham Land, the 

 United States, and South Victoria Land. Some have been collected 

 from the snows of frozen mountain tops while others are found at 

 sea-level, or below, in caves and caverns in the hottest climates. 



They are very delicate, often minute, soft-bodied insects, covered 



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