74 MICROSCOPIC ILLUSTRATIONS. 



be kept several days without food, and by this exinani- 

 tion its structure becomes considerably more transpa- 

 rent*, while its natural ferocity is greatly increased, so 

 that it will attack and fight with creatures much larger 

 than itself, and even with its own species. It may be 

 remarked, that it studiously avoids any contest with the 

 Nepa, or water- scorpion. 



On a fine sunny day the larvae rise to the surface of 

 the water, and delight to bask in the sun ; but if watched, 

 they remain motionless, with their claws extended. If a 

 stick, or any other substance, be presented to them, they 

 will immediately seize it, and will sometimes suffer them- 

 selves to be cut into pieces before they relinquish their 

 hold. Their bite has been considered poisonous by many 

 persons, as it takes a greater length of time to heal than 

 other wounds of the same extent : so that caution should 

 be used in taking them. 



Touching the anatomy of this creature, it may be ob- 

 served, that the sucker, marked d, is contained in a crus- 

 taceous sheath, and may be considerably protruded or 

 completely withdrawn at the pleasure of the larva : in 

 the engraving it is shewn extended to about three 

 quarters of its length. The eyes are compound, but 

 of a peculiar formation, consisting of seven oval aper- 

 tures, arranged like leaves upon a branch : in the draw- 

 ing they are denoted by the letter e. The whole of the 



* Dr. Goring kept the subject represented in the engraving some time 

 without food, in order to render its interior organization more clear : it 

 may be observed that its intestinal canal is quite empty. 



