436 THE CHAMELEON FLY. 



sects. The egg from which it is produced is de- 

 posited by the female in the hollow stalks of reeds 

 and other aquatic plants. From this proceeds a 

 larva of singular structure, which is often to be seen 

 crawling on grass and plants near shallow standing- 

 waters, or floating near the surface. 



The general colour of the larvae is a greenish 

 brown. Their bodies consist of eleven rings, and 

 their skin somewhat resembles parchment. Though 

 these animals, before their transformation into flies, 

 live in water, air is necessary to support their prin- 

 ciple of life ; and the apparatus with which nature 

 has furnished them for that important purpose de- 

 serves our particular notice. The last ring or ter- 

 mination of their bodies is open, and serves as a 

 conductor of air. From this ring proceed a number 

 of hairs, which, when examined by the microscope, 

 are found to be real feathers with regular vanes. In 

 particular situations the larvae bend the last ring in 

 such a manner as to reach the surface of the wa- 

 ter or mud in which they are placed. The feathers 

 prevent the water from entering the tube or organ 

 of respiration ; and, when the animal raises the ter- 

 mination of its body to its surface, in order to re- 

 ceive air, it erects and spreads the feathers, and by 

 these means exposes the end of the tube to the at- 

 mosphere. When it wishes to descend, it contracts 

 the filaments into the form of a ball, and the bubble 

 of air contained within it serves to keep the body in 

 a vertical position. 



If this insect be cautiously cut open, two large 

 vessels, or trachea?, will be seen on each side to oc- 



