LAKE TO FOREST OR PRAIRIE 



241 



first two attach their nests to the cat-tails which are fastened 

 together in a loose cluster for the purpose. In these two zones 

 one finds also Virginia, king, and sora rails, Florida gallinules, 

 coots, herons, and sandpipers. The muskrat builds his dome- 

 shaped house of the cat-tails, together with vegetable debris 

 raked up from the bottom. 



Pushing out from shore into the rush and cat-tail zone is 

 the shrub zone. The buttonbush or elbowbush is the pioneer. 

 Back of it comes such shrubs as prickly ash, an aromatic plant 

 with odd pinnately compound leaves and prickers on the 

 stems; maple-leaved viburnum, red-osier and silky dogwoods; 



Fig. 344. — The pickerel frog 



and still farther back comes the white ash-elm forest association 

 with the ash the predominant tree. Neither the ash-elm forest 

 nor the shrub zone at its margin is marked by many strikingly 

 distinctive animals. The black-sided grasshopper, Xiphidiiim 

 nigropleura, is common on the shrubs and below them. The 

 striped shrub crickets, the Texan katydid (Fig. 348), the oblong- 

 winged katydid, and the forked-tail katydid (Fig. 347) are so 

 prevalent that the shrub zone may justly be called the katydid 

 zone. At times the larva of Papilio cresplioiites is found freely 

 on the prickly ash, as in the summer of 192 1, but usually the 

 giant swallowtail is rare about Chicago. When the shrubs are 

 in blossom many gnats and flies are hovering about them, and 



