256 THE LIFE OF AN INSECT. 



pupa state will last until June in the next year : 

 thus manifestly teaching us that according as the 

 weather is mild and genial the pupa state will be 

 shortened ; or according as it is cold and rigorous 

 it will be increased in duration. The ingenious 

 Reaumur determined to put these singular facts 

 to an experimental test ; and as his results are in 

 the highest degree interesting and important, we 

 shall proceed to submit an abstract of them to 

 the reader's notice. 



In casting about for the means of exposing the 

 pupae he was about to experiment on, to a warm 

 and equable temperature, Reaumur determined to 

 conduct his first experiments in the Royal Con- 

 servatories, which were always carefully heated, 

 and in which, as he with French naivete expresses 

 it, " summer reigned in the depths of winter." In 

 the month of January he carried thither a number 

 of boxes containing pupse of different species. The 

 result was precisely what he had expected: in 

 the midst of a severe winter a number of butter- 

 flies appeared in his boxes, many of which would 

 not naturally have made their appearance until 

 the months of May, August, or even September ; 

 thus shortening the pupa state from four, seven, or 



