156 A NATURALIST IN THE GREAT LAKES REGION 



In the plant associations there is a sharp demarcation between 

 the fore-dune and the cottonwood zone that comes next, for the 

 cottonwoods add a strikingly new feature. There is no such 

 separation in the animal associations, and both fore-dune and 

 cottonwood areas may be included in the one digger wasp 

 association. True, certain new 

 animals appear. The kingbird finds 

 the tops of the cottonwoods excellent 

 lookouts from which to spy the in- 

 FIG. 154. Maritime locust, sects upon w hi c h he feeds. But he is 

 Trimerotropis maritima. more common and more character- 



istic in other situations as, for instance, along the borders 

 of the woods. The tree swallow nests in the hollow stumps 

 of old pines and cottonwoods. Their backs are iridescent 

 blue green; their throats, breasts, and bellies, pure white. 

 Bank swallows nest in the steep sides of dunes, especially 

 where blow-outs make sand cliffs 

 (Fig. 1 53) . The cottonwood is rela- 

 tively free from the insect pests that 

 usually accompany it. The cock's 

 comb gall is not frequent on it here. 

 Such a characteristic woodborer of 



, T-,, , 7 7 FIG. 155. Mottled sand locust, 



the cottonwood as Plectrodera seal- Sparag j o 5 n wyomingianum . 



ator is rare. In the spring when the 



tree is in blossom certain flies and beetles are attracted by its 

 abundant pollen, but these are also common on the willows of 

 the fore-dune. The white or maritime and long-horned locusts 

 are frequently found in the digger wasp zone, though they are 

 also found in the bronze tiger zone. 



The female of the maritime locust (Fig. 154) is about 1.2 

 inches long; the male, about . 8 of an inch. The animal is light 

 gray to reddish brown in color, the under side almost white. It 

 is so near the color of the sand as to be nearly invisible until it 

 flies. The inner wings have a dark band along the margin but 

 a transparent tip. The inner face of the hind femur bears three 



