METAMORPHOSIS 



245 



Larva. When the eggs have hatched, the larva- may 

 be reared upon bran. Note the changes during growth. 

 Describe the process of 

 pupation. 



The Pupa. What is its 

 color ? Does the adult 

 emerge through the side 

 or the end of the pupa- 

 case ? How does the 



front of the head of the FIG 189 Foot of house . fly . Greatly 

 newly emerged fly dif- enlarged. 



fer from that of the same fly several hours later ? How 

 is the opening in the pupa-case made? 



Adult. Place fly under a glass vessel (a plain, thin 

 water-glass will do). Rest the inverted glass upon 

 black paper on which a few grains of granulated sugar 

 have been placed. ISTote the manner in which the fly 

 feeds upon the sugar. Place within the glass vessel 

 substances sweet and sour, neutral and of various colors, 

 such as different colored sugar, salt, molasses, vinegar. 

 What substances seem to attract the fly most ? What 

 particular quality seems to form the greatest means of 

 attraction ? AVhat senses seem to be relied upon in the 

 discernment of these various substances? 



COMPANION BOOKS. 



A Manual for the Study of Insects, .1. H. and A. B. Corn- 

 stock. Comstock Publishing Company. Ithaca, N. Y., 1895. 

 Price, $3.75, net; postage, 34 cents. 



The Life of a Butterfly, S. H. Scudder. Henry Holt & Com- 

 pany. New York, 1893. Price, $1.25. 



Everyday Butterflies, S. H. Scudder. Houghton, Mifflin & 

 Company. Price, $2. 



First Report of the U. S. Entomological Commission. ( This 



