TEOPICAL AQUAEIUM FISHES 203 



Enemies of Aquatic Plants. The most serious enemies are musk- 

 rats. These eat the roots of several hardy aquatics, particularly over the 

 winter season. They are partial to the roots of the small yellow water 

 lily, Pygmaea helvola. 



Fig. 155. Aqu.\tic Cut-Worm 



A leaf-cutting worm {Hydro cam pa), sometimes becomes quite a 

 nuisance. It cuts a piece from the edge and, laying it on the leaf, attaches 

 the two together and uses the two pieces as a cocoon. Loose bits of 

 water lily leaves. Sagittaria, etc., observed floating around will, if pried 

 apart, often be found to contain this white worm. The accompanying 

 illustration is of life size. 



