ROACHES AND OTHER ANCIENT INSECTS 



beds of the Carboniferous deposits, when insects were 

 already fully winged. This fact shows how cautious 

 we must be in making negative statements concerning 

 the extinct inhabitants of the earth, for we know that 

 insects must have lived long before we have evidence of 

 their existence. The absence of insect fossils earlier than 

 the Carboniferous is hard to explain, because for millions 

 of years the remains of other animals and plants had 



Fig. 57. Machilis, a modern representative of ancient insects before the 

 development of wings. (Length of body . 5 ie inch) 



been preserved, and have since been found in compara- 

 tive abundance. As a consequence, we have no concrete 

 knowledge of insects before they became winged creatures 

 evolved almost to their modern form. 



At the present time there are wingless insects. Some 

 of them show clearlv that thev are recent descendants 

 from winged forms. Others suggest bv their structure 

 that their ancestors never had wings. Such as these, 

 therefore, may have come down to us bv a long line of 

 descent from the primitive wingless ancestors of all the 

 insects. The common "fish moth," known to entomolo- 

 gists as Lepisma, and its near relation, Machilis (Fig. 57), 

 are familiar examples of the truly wingless insects of the 

 present time, and if their remote ancestors were as fragile 

 and as easily crushed as they, we may see a reason why 

 they never left their impressions in the rocks. 



Along with the Carboniferous roaches and the Paleo- 

 dictyoptera, there lived a few other kinds of insects, 

 many of which are representative of certain modern 



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