CONTROLLED PUPATION 83 



burned or otherwise disposed of. So it is with the tissues of the 

 maggot. From the old house we save the plumbing, the wiring and 

 the kitchen range, which corresponds in the maggot to the repro- 

 ductive glands, the nervous system and the heart, which are left in- 

 tact, or at most altered and attended to. 



At length it becomes time for the painters and decorators. Nature 

 employs a vast army of these. In the keg, after ten days, the milky 

 white and partly transparent, but otherwise perfect insect commences 

 to receive its color. It appears first in the eyes with an influx of 

 emerald green pigment studded with golden, microscopical dots, 

 which are followed in forty-eight hours by the appearance of black 

 patterns upon the legs and wings, due to more or less dense hairs 

 upon these appendages into which the color gradually flows. Upon 

 the back of the head there is a pattern of hairs and another of longer 

 ones upon the thorax, while the abdomen likewise suddenly appears 

 clouded with pubescence. Further than this no ground color or 

 markings can be seen, owing to the color being much like the shell 

 of the keg itself. 



In another forty-eight hours, fourteen days after pupation, the fly 

 emerges by splitting the head of the pupal keg in two equal parts. 

 This is a simple operation, as the shell is not too substantial, but 

 the new-born fly has yet another task, before it will be free. It has 

 yet to dig a passage from its tomb to the light of day. It must be 

 done quickly, lest the wings fill and dry too small and their use- 

 fulness be lost. 



For this purpose the insect is supplied with a battering ram, which 

 protrudes between the eyes at birth from the pupal case. It is a trans- 

 parent sack-like appendage which may be expanded or contracted 

 at will by the fly. It contains no apparatus of any kind, but is ap- 

 parently the forehead of the insect capable of expansion. To watch 

 the operation of this strange appendage is remarkable. First, it 



