650 EXPERIMENT STATION RECORD. 



the yellow pine increases the difficulty of control. It is stated that the proximity 

 and abundance of the alternate host of P. filamentosum, CastiUeja miniata, and 

 its prolific development on the lodgepole pine in the vicinity of the seedling 

 beds tend to make this a dangerous disease in forest nurseries. 



The receptivity of oak for Oidium, B. Pantanelli (Bid. Otto Bot. R. Univ. 

 NapoU, 4 U9W, pp. 309-348, pis. 3, figs. 8).— Giving the results of studies on 

 the relations of susceptibility, as regards attack by Oidium, to foliar structure, 

 turgescence, chemical character, etc., the author states that the fungus shows 

 preference, in case of Quernis pedunctilata and Q. piihescena, for portions which 

 are in a growing condition when exposed to infection. 



The principal structural difference between foliage which is resistant (none 

 is immune) and that which is receptive is .said to be in the inferior development 

 of the mesophyll In the latter, and in its general immaturity. Epidermal struc- 

 ture and cuticular thickness show no relation to susceptibility. 



The average concentration of the cell sap is greater in the resistant than in 

 the receptive leaves, but the elastic tension of the cell walls is greater in case 

 of the latter whether or not they are attacked by Oidium. 



The distribution of plastic carbohydrates shows in receptive cells a low degree 

 of activity, so that development is checked and remains comparatively back- 

 ward in these. The receptive leaves contain less organic nitrogenous materials 

 as compared with inorganic constituents. The conditions of receptivity appear 

 to be static with an excess of in.soluble over .soluble nitrogen. 



The content of mineral substances in the leaf is not related to its receptivity 

 except as it is an Indication of an immature condition of the leaves. The recep- 

 tive leaves are richer in .soluble pho.sphorus than those relatively resistant. 



A bibliography is appended. 



Control of pine rust, Schuxtz (Ztschr. Forst u. Jagdir., Jfl (ifl/.5). .Vo. i. pp. 

 8-29, figs. 5). — The author states that he has confirmed the conclusion of 

 Haack (E. S. R., 31, p. 153) to the effect that infection by pine rust occurs on 

 the young needle-bearing shoots. It is said also that the fungus may kill young 

 shoot tips before reaching its fruiting stage. 



Removal of affected trees steadily reduced the infection. 



ECONOMIC ZOOLOGY— ENTOMOLOGY. 



Digest of the game, fish, and forestry laws, edited by .7. Kalbfts {Ilarris- 

 burg, Pa.: State, 1915, pp. .3.'/2).— This pamphlet, published biennially (E. S. R., 

 32, p. 150), contains the text with indexes of the laws of Pennsylvania on game, 

 fish, and forestry, and leading discussions relating thereto. 



The food of birds, Lavka Florence {Trans. Highland and Agr. Soc. S^cof., 

 5. ser., 27 (1915), pp. 1-53). — In this report of work carried on in continuation 

 of that previously noted (E. S. R., 31, p. 547) the results of examinations of the 

 crop contents of 891 birds, representing a large number of species, are reported 

 upon. 



Bird houses and nesting boxes, E. H. FoRBt'sii {Mass. Bd. Agr. Circ. 1ft 

 (1915), pp. 2.'h pis. 8, figs. 33). — This circular describes and gives plans and 

 illustrations of bird houses and nesting boxers. 



Attraction and protection of birds, G. Wolda (yogclcultitur. The Hague: 

 Dept. Landb., Xijv. en Handel, 191^. pp. 26. pis. 2, figs. 16). — Methods of at- 

 tracting birds are described and illustrations and plans of bird houses and 

 nests are given. 



How to attract wild birds about the home, N. M. Ladd (Greentcieh, Conn.: 

 The Oreenuieh Bird Protective Socictp, Inr., 1915, pp. 68. pi. 1, figs. .}6). — A 



