Insects of the Coal Period. 



Dragon-flies were minierous in the period of the coal formation, and some of them were of enormous size. The one represented in 

 the upper part of the picture was found at Coinmentrv, in France, and measured more than two feet across its expanded wnigs. Below 

 (centre) is an enormous may Ifv, and to left and right of it a large species of earwig and a cockroach of that period. 



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