THE HOUSE FLY. 15 



THE HOUSE FLY. 



THE PARTS OF THE BODY. 



1. The head, the foremost, or anterior part. 



2. The thorax, or middle portion. 



3. The abdomen, the hinder, or posterior part. 



THE HEAD. 



1. Examine the eyes with a strong lens, and under a low- 

 power of the microscope, to discern its parts or facets. 

 Such an eye is said to be compound, and in the fly is 

 composed of about 8000 parts ; what shape have the 

 facets ? 



2. Cut off the head, lay it on a glass slide, and with a 

 one-inch objective examine the short antennae in front 

 of the head. 



3. Look on the top of the head for simple eyes. 



4. With a lens examine the under part of the head to 

 see the tongue. How does it move ? Remove it and 

 look at it with a one-inch objective. How is it used? 



THE THORAX. 



1. How many legs are there ? To what are they attached? 

 How many segments has each leg ? 



2. The wings ; how many are there ? Back of each wing 

 find a short membrane, the winglet. Xote the folded 

 portion connecting the wing and the winglet. 



3. A little further back are two slender knobs project- 

 ing on stalks like pins; these are the balancers, and 

 are considered as representing the hinder wings found 



