139 



specimen was captured during August at Havana, 111. Felt ('06, p. 

 582) records seniculus as from hickory and butternut. Attclahus 

 rliois Boh. was taken July 4, on hazelnut, at Bloomington. It is re- 

 corded from sumac, dogwood, alder, and oak. 



For lists of Coccidcc living on woodland (and other) shrubs see 

 Cockerell ('97). 



4. The forest Croivn Coninmnity 



Instead of next turning to the animals of decayed wood on the 

 forest floor, I wish to begin at the other end of a series, with the ani- 

 mals of the living tree, and then to follow an order which passes pro- 

 gressively through enfeebled, dying, fermenting, seasoned, and solid 

 wood to all stages of its decay. The decay of a fallen trunk commonly 

 begins with the sap-wood, thus loosening the bark, and extends in- 

 ward until the whole becomes soft or is changed to brown powdered 

 wood, which gradually changes to humus. This is a series of progres- 

 sive humification, and, speaking in general terms, follows the course 

 through which all forests tend to pass; although fire, flood, and ani- 

 mals, including man, divert much wood from such a fate. 



To investigate such a series fully is far beyond the scope of the 

 Charleston studies, and yet our material, supplemented to some de- 

 gree, mav serve at least to outline one. The difficulties of studying 

 the animals of the forest crown are serious, and so far as known to 

 me no comprehensive work on this community has been done in this 

 country. Many members of it have been studied individually, but 

 the animals have not been studied as a community. About the 

 woodland insects a vast fund of facts has been accumulated in the 

 study of the economic problems of shade, fruit, and forest trees; 

 furthermore, investigations have shown that among the invertebrates 

 insects have a controlling or dominating influence in the forest. But 

 the relations of the other forest invertebrates to the forest crown have 

 received very little attenion from our students. 



The animals of the forest crown, and particularly those of the 

 foliage, are more exposed to changes of temperature, moisture, wind, 

 and evaporation than those below the crown and protected by it. With- 

 in the crown there are, in fact, an upper, exposed part, and the lower, 

 protected part. Many of the animals of the forest crown live rela- 

 tively free from the influence of the substratum, as other animals in 

 the open water are similarly free from the influence of the bottom. 

 Others divide their time, part of it being spent in or on the earth, and 

 a part of it in the trees. Conditions of poor ventilation, darkness, 

 density of medium, relative stability, excess of moisture, and cor- 

 responding conditions in the soil, are here replaced by conditions of 



