1 86 A NATURALIST IN THE GREAT LAKES REGION 



FIG. 21 zA. Some aquatic insects and nymphs. After P. S. Welch, a, stone-fly 

 nymph; b, May-fly nymph; c, whirligig beetle larva; d, black-fly larva; e, damsel- 

 fly nymph; /, water tiger; g, larva of water scavenger; h, the dobson; i, diving 

 beetle; j, giant waterbug; k, smaller waterbug; I, water-scavenger beetle. 



