234 



DRY AND MESOPHYTIC FOREST COMMUNITIES 



forest temporary ponds. Beneath the leaves and wood are snails 

 (Zonitoides arboreus), millipedes {Polydesmus sp.), and centipedes (Litho- 

 bius sp.), and in dry weather Polygyra thyroides and multilineata. 

 Ground beetles and rove-beetles are common. One finds Cicindela 



Fig. 212. — The oak tree-hopper {Telamona querci) (after Lugger). 



sexguttata, the green tiger-beetle, here rarely; it is much commoner in 



later stages, however. 



In the decaying logs and stumps are darkling beetles (156), numerous 



wireworms (Elateridae), and myriopods. Sometimes fungus-feeding 



beetles (Diaperis hydni and Eustrophus tormentosus) are present in 



numbers. Ants are also often 

 abundant. Carpenter ants are 

 common. The aphid housing 

 ant (Lasius umbratus subsp. 

 mixtus var. aphidicola) is some- 

 times abundant. In autumn 

 certain galleries in the wood 

 are crowded with woolly aphids 

 which are the so-called "cows" 



Fig. 213. — The oak plant-bug (Hyallodes 

 vitripennis) (from Washburn after Riley) : 

 a, young; b, adult. 



which the ants house for the 

 winter. 



b) Field and shrub strata. — 

 In moist weather the snails (Polygyra) mentioned above are common 

 on the herbaceous vegetation, while the tree-frogs (Hyla versicolor and 

 pickeringii) (139) are common, and spiders are numerous. 



c) Tree stratum. — The oaks (137) are affected by many of the same 

 species as in the earlier stages. The tree-frog is sometimes found in the 



