PI. X. — Summer life in the quiet shallows: i, broad-leaved 

 arrowhead; 2, white water lily; 3, Elodea; 4, Myriophyllum; 5, 

 6, 7, dragonfly, Libellula pulchellu (5, nymph; 6, cast 

 skin of nymph; 7, adult); 8, 9, diving beetle, Dytiscus (8, 

 larva; 9, adult); 10, adult backswimmer, Notonecta; 11, leaf- 

 beetle, Donacia; and 12, holes through which Donacia lays 

 her eggs; 13, whirligig beetle; 14, caddis worm, Tricenodes; 

 15, water-mite; 16, fresh water sponge green with algas; 17, 

 nymph of mayfly, Callihatis. 



