LAKE TO FOREST OR PRAIRIE 



239 



rice (Fig. 338); water-reed, Phragmites communis (Fig. 339); 

 sweet flag (Fig. 340). 



Along the margin of the open water soft-shell, musk and 

 geographic turtles are to be expected. The first is easily known 

 by its leathery rather 

 than bony shell; the 

 second, by its musky 

 odor; the third, by 

 the fine lines on each 

 bony plate of the 

 shell that give an 

 appearance some- 

 thing Uke a map. 

 Farther in shore in 

 the zone of submerged 

 plants, especially in 

 the bays, are many 

 adult and larval in- 

 sects that may be 

 dredged up with the 

 plants. The top min- 

 now, Fundulus dispar, 

 is common (Fig. 434). 

 Among the insects are 

 the water scorpion, 

 giant water bug, 

 water boatman, many 

 diving beetles of the 

 families Dytiscidae 

 and Hydrophylidae, and May-fly nymphs. Dragon and damsel- 

 fly nymphs are common, and the molt skins of the latter are 

 commonly found on the rushes and cat-tails. A few of the 

 more frequent dragon flies are Anax Junius, Gomphus spica- 

 tus, and Libullula pulchella. These insect larvae are already 

 famiKar from the study of the interdunal ponds, as are also the 



Fig. 341. — The painted turtle 



