ANIMALS OF THE DUNES 



165 



including the oak apple, the empty apple, the petiole gall, the 

 wool gall, the midrib gall, the bullet gall, the seed gall, etc. 

 (Fig. 172). 



With the advent of the red and 

 white oaks in the mixed oak asso- 

 ciation conditions begin to approxi- 

 mate those of the mesophytic 

 climax forests, the oak-hickory and 

 the maple-beech. The soil is well 

 supplied with humus. The shade 

 is deep enough to prevent excessive 

 evaporation and to afford cover for 

 the pioneers of that whole group of 

 animals that belong to the cool, 

 dark, moist recesses of these FlG ' I73 -~ Tree toad ' 

 climax forests. Earth-worms begin to appear. The holes of the 

 woodchuck are common and the mole exca- 

 vates his subterranean passages. Such snails 

 as Zonitoides arboreus, Polygyra thyroides, and 

 P. profunda are found under the bark of de- 

 caying trees, under logs, or crawling on the 

 shrubs in moist weather. They are by no 

 means so common as they are in the later 

 association. Millipedes and centipedes are 

 found under the bark of old logs. The car- 

 penter ant makes its chambers in the decay- 

 ing logs and stumps, and the aphid housing 

 ants use such passages as stables for their 

 "cows," the plant lice; it carries these 

 FIG. 174. Tree through the winter in such sheltered retreats 

 toad, Hyla pickeringii. so it can pasture them out in spring on the 

 tender vegetation. Herbaceous plants are now numerous, and 

 there is an abundant insect population on them. Bumblebees, 

 honeybees, and wasps are common. Butterflies are abundant 

 the monarch, viceroy, spangled fritillary, wood satyr, wood 



