Periodical Literature. 479 



8. The gradual dying is a kind of preservation of wood, the 

 artificial killing causes an accelerated decomposition. 



Ueber die Krdfte welche das Emporsteigen des Wasscrs in unsren Nadel- 

 holzern und Lanbholzeni vernrsachen. Allgemeine Forst- u. Jagdzeitung. 

 June, 191 1. P. 204. 



The removal of the litter from the forest 



Insects floor reduces, according to Dolles, the va- 



and riety and number of insects in the forest. 



Forest Floor. This is a detriment, since the reduction is 



least among those insects which are injuri- 

 ous to the forest because their food supply remains undisturbed. 

 It is greatest among those neutral species which live in the leaves 

 and grass on the ground. These species are called neutral be- 

 cause they neither attack trees nor prey upon other insects which 

 are injurious. But they have an important function in that dur- 

 ing the absence of noxious species they serve as hosts upon 

 which beneficial parasitic insetc are propagated and as prey 

 for predatory species keeping these alive in sufficient numbers 

 to render effective service in combating a sudden outbreak of 

 injurious insects. 



Parasites do not confine their attacks to weakened individuals, 

 but once parasitized, the insect is weakened to a degree which 

 prevents it from pushing deeply into the soil to pupate. Most 

 parasites accordingly develop in the ground cover or on the 

 surface of the soil and are either removed with the litter or 

 are eaten by birds after the litter is removed. The healthy 

 individuals of the injurious species are undisturbed because they 

 pupate deep in the soil. 



The preservation of the ground cover further checks the de- 

 velopment of insect pests by affording nesting-places for many 

 insectivorous birds and ants and by harboring entomogenous 

 fungi. 



EinHuss der Streunutsung auf die Vermehrung imserer Waldschddlinge. 

 Silva IV. Feb., 191 1. Pp. 49-50; 59-61. 



