ECONOMIC ZOOLOGY — ENTOMOLOGY. 547 



Larch, mistletoe: Some economic considerations of its injurious efiEects, 

 J. R. Weir (U. S. Dept. Ayr. Bui. 311 (1916), pp. 25, figs. 13).— In this bulle- 

 tin the author gives an account of some of the practical results secured in an 

 investigation of the injurious effects of the larch mistletoe (Razoumofskya 

 laricis) occurring in the Blue Mountain region of Oregon and the vicinity. 



Tlie deterioration of the western larch in some of the open, exposed stands 

 is said to be due to this mistletoe, which attacks trees of all ages, from seed- 

 lings to the unsuberized parts of mature trees. If the infected trees are not 

 entirely suppressed or killed early in life they are so injured as seldom to 

 produce a good grade of timber. Two types of infection are said to occur, one 

 by the seed falling on the branches where witches' brooms develop, and the 

 other by the gradual advance of the cortical root system of the mistletoe 

 along the branch to the younger tissues. 



For the control of this pest the author recommends inserting a clause in 

 all timber-sale contracts requiring the cutting of all larches infected with 

 mistletoe, whether merchantable or not. 



Trametes pini in India, R. S. Hole (Indian Forest Rec, 5 (1914), No. 5, pp. 

 159-184, pis. 8). — This contains the more important results of a study con- 

 tinued since 1911 on T. pini attacking Pinus excelsa. Although this disease was 

 first definitely identified in the Punjab in 1904, it is not regarded as of recent 

 origin in India, where it is now causing severe loss. 



Infection usually occurs at wounds from wind-blown spores, the spread being 

 greatly favored by the practice of lopping, which is prevalent in the Punjab 

 hills. Natural root grafting, while very common, is not regarded as a very 

 important means of transmission. 



Measures recommended are preventive only, the areas which are seriously 

 affected requiring generally complete restocking with resistant trees. Those 

 less seriously diseased are protected by cutting affected trees below the surface 

 of the soil, which is then spread deeply over the cut surfaces. Uninfected 

 forests require hygienic measures and protective belts on sides adjoining in- 

 fected areas. The establishment of mixed in preference to unmixed pine forests, 

 where practicable, will reduce the danger of infection. 



A list is given of species attached by T. pini in Europe, America, and Japan, 

 also a short bibliography of this disease. 



Degradation of wood by fungi, C. Wehmer (Ber. Deut. Chem. Gesell., 48 

 (1915), No. 2, pp. 130-134; abs. in Jour. Chem. Soc. [London], 108 (1915), No. 

 630, I, pp. 197, 198).— In pursuance of previous work (E. S. R., 33. p. 651), the 

 author reports the percentage composition of conifer wood after being subjected 

 to the action of Merulius, the results as regards cellulose being still under in- 

 vestigation. 



It is stated that free organic acid is absent from rotten wood, the reaction 

 observable being attributed to the presence of humus. 



Studies are in progress with M. Sylvester, Coniophora cerebella, and Poly- 

 porus vaporarius, which also destroy structural timber. 



ECONOMIC ZOOLOGY— ENTOMOLOGY. 



An account of the mammals and birds of the lower Colorado Valley, with 

 especial reference to the distributional problems presented, J. Gkinnell 

 (Univ. Cal. Pubs., Zool., 12 (1914), No. 4, pp. 51-294, pis. 11, figs. 9).— This 

 report is based upon three months' work in the field, during which 1,272 speci- 

 mens of mammals, 1,374 of birds, 443 of reptiles and amphibians, etc., were 

 collected. 



