INSECTS : THEIE BEEATHING OEGANS. 



117 



The curious faculty of repelling water, which the 

 interior surface of this plumy coronal possesses, is of 

 the highest Talue in the economy of the insect ; for, on 

 the one hand, it permits the breathing orifices to be 

 brought into contract with the air, even when nearly a 

 quarter of an inch below the surface ; and on the other 

 hand, it allows the volume of air inclosed within the 

 funnel to be perfectly isolated and carried securely 

 away, as a reservoir for the wants of the animal, when 

 engaged in its avocations 

 of necessity or pleasure, in 

 the recesses of its sub- 

 aquatic groves. It is re- 

 markable that so complete 

 is this repellent power, that 

 when the tail is at the sur- 

 face, the animal may make 

 a very perceptible descent 

 without breaking the con- 

 tinuity of the air, the sur- 

 face presenting the curious 

 phenomenon of a deep fun- 

 nel-shaped dimple leading 

 dovsm. to the tail of the 

 animal. 



The chameleon-fly is 

 not, however, so abundant 

 and so universally distrib- 

 uted as that you may al- 

 ways calculate upon being 

 able to repeat these obser- 

 vations when you will. I shall, therefore, show yon an 

 analogous example, much more easily obtained. Both 



GETJB OF cnAMELEON-FT.T. 



