INTERDUNAL PONDS AND TAMARACK SWAMPS 187 



Fig. 212B. — Aquatic insects and nymphs. After P. S. Welch, a, adult mos- 

 quito, b, its larva; c, its pupa; d, water skater; c, marsh strider; /, whirligig beetle; 

 g, water scorpion; h, water boatman; /, back swimmer. 



