218 DRY AND MESOPHYTIC FOREST COMMUNITIES 
by incidental forms, such as the Carolina locust (Dissosteira carolina ?) 
(40), with occasionally the red-legged locust (Melanoplus femur- 
rubrum) and the two-lined locust (Melanoplus bivittatus). Under rock 
fragments we took the ground beetle (Anisdactylus interpunctatus) and 
the common cricket (Gryllus pennsylvanicus). Hancock (40) states 
that the smooth cockroach (Ischnoptera inaequalis Sauss) and the large 
cockroach (J. major Sauss) occur in such situations. We found the nest 
of a spider (A gelena naevia) attached to one of the loose rocks. 
Other stages have been studied only superficially. In the cracks 
and crevices of rocks and rock piles, shrubs and vines grow and the 
young forest, field, and shrub strata have all the appearance of the 
shrub stage on clay at Glencoe. The animals are for the most part those 
common to thickets. 
IV. Forest COMMUNITIES ON SAND 
In chap. iii, pp. 46, 47, we discussed sand areas and their distribu- 
tion. In chap. viii we noted the series of ponds and ridges with a little 
regarding their origin (pp. 136-40). Their general relations are indicated 
by Figs. 83, p. 137, and 84, p. 139. It appears that the margin of the lake 
may, under conditions of rapid recession, become the margin of an inland 
pond. Under condition of slower recession this belt may be buried and 
hence come to lie beneath such belts as lie farther inland. Since the 
sand areas about Chicago represent all the stages in the development 
of forests, beginning with the bare sand and ending with the beech 
forest, it is my purpose in the remainder of this chapter to follow the 
animal associations and formations of forest development. Some of the 
stages will be taken from till areas, but this is because these stages are 
more extensive than the corresponding stages on the sand deposits. 
The chief stages are the wet sand of the water margin, the middle 
beach, the cottonwoods, the old cottonwoods and pine seedlings, the 
pines, the black oak, the black oak and white oak, the black oak-white 
oak-red oak, the red oak-white oak-hickory, the basswood-red oak- 
white oak-maple in moister places, and the beech and maple. 
I. THE WATER MARGIN ASSOCIATION 
(Stations 56, 58; Table XX XVIII) 
One morning early in June, we walked along the beach of Lake 
Michigan for a mile and a half, for the particular purpose of studying 
the animals of the zone within the reach of waves. Animals were few, 
only stragglers of the regular residents which we have noted on p. 151. 
