PI. III. — I. In running water some animals are active 



all winter; insects, snails, and planarians creep over the stones 



and salamanders skulk beneath them. 2. Insects emerge 



from the rapids by hundreds, and the fly-catching phoebes 



take a plentiful harvest from the air; in the jostling water 



small animals find safety by holding on or getting under 



cover. 



Photo, by A. H. Morgan 



