TROPICAL AQUARIUM 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. 
Fic. 155. Aguatic Cut-WorM 
A leaf-cutting worm (Hydrocampa), 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. 
