INSECTS. 



119 



Similar cases encrusted with carbonate of lime are found in 

 Auvcrgne, in France, forming strata six feet in thickness, and 

 extending over a considerable area.* 



Fig. 103.— Epdemera. 



The Ephemera {Fig. 1 03), whose brief period of existence 

 in its perfect state has become proverbial, belongs also to this 

 division. He who reads Dr. Franklin's charming paper f con- 

 taining the soliloquy of an aged Ephemera, who had lived 

 " no less than four hundred and twenty minutes," will ever 

 afterwards look with interest upon the insect Avhich has been 

 made the means of conveying a lesson so true and so com- 

 prehensive. 



HYMENOPTERA.J 



Fig. 104.— TE.^T^REDO. 



Fig. 105.— ICDRKUMOS. 



The insects of this order have four veined membranous 

 wings, but they are not equal in size, nor are they reticulated, 



• Lycll. Principles of Geology, voL iv. p.ige 165. 

 t Tlie Ephemera, an Emblem of Hnm'an Life. 



X From two Greek words; one signifying a membrane, the other a 

 u'j;iy, all the four wings being membranous. About 1100 Irish species. 



