65 



Injured plants should not therefore be condemned too quickly. The 

 stimulation to growth may be due to two factors, namely, the increased 

 activity of the catalase and the increased permeability of the cell- walls, 

 allowing readier exchange of food materials and of gases. All other 

 physiological effects of the presence of hydrocyanic acid in a plant are 

 secondary to the disturbance of the oxidase and catalase activities. 

 A bibliography of 26 works is given. 



Shtcheebakov (Th.). flonycTMMo-nM onpbiCKMBaHie MbimbnKo- 

 BMCTWMM npenapaiaMM ciwieHHoro KpacHaro Kneeepa ? [Is the 



Spraying of Red Seed Clover with Arsenical Preparations permis- 

 sible'?] — Reprint from « Xo3flMCTBO.» [Husbandnj], Kiev, 

 nos. 9-10, 1917, 8 pp. [Received 19th December 1917.J 



The author in some of his previous works has refused to acquiesce 

 in the generally accepted view that Apion is injurious to clover, and 

 he deals in this article with the recommendation of A. A. Sopotzko as 

 to the sprapng of clover with Paris green. On the strength of his own 

 observations and experiments he insists that such spraying is not only 

 not useful, but is actually harmful, as it gives rise to the poisoning of 

 the fertihsing bumble-bees and thus to a decrease in the crop of clover 

 seed. No spraying operations ought to be undertaken either during 

 the blossoming of clover or even before that, in April and May, when 

 the queen bees are on the ^ving. 



Shtcheebakov (Th.). KaKT» fltMCTByeTi) noAKamnBaHie Ha KpacHbiti 

 KJieBep"b ? [Tlie Effect of Mowing on Red Clover.]— Reprint from 

 « BtCTHMK-b CeJlbCHaro X03flMCTBa.» [Messenger of Agriculture], 

 Moscoiv, 1917, 50 pp. [Received 19th December 1917.] 



The cutting of clover in June [see this Review, Ser. A, iv, p. 298] is 

 ■one of the remedies recommended for the control of Apion. The 

 author, who does not believe in the injuriousness of these weevils, 

 is inclined to regard this remedy as injurious rather than beneficial to 

 the growth of clover. As far as another pest of clover, BruchopJiagus 

 gibhus, Boh. [see this Revieiv, Ser. A, iii, p. 8] is concerned, some figures 

 obtained by the author show that it can hardly be regarded as of 

 serious consequence. 



Shtcheebakov (Th.). Flo noBOAY T. H. rpymeBaro TpMnca btj Kpbiwiy. 



[Ahont Euthrips pyri,Dame\,iritheCiimea,.] — Reprint from " The 

 Transactions of the Museum of the Zemstvo of Taurida ""for 1914, 

 Sitnferojwl, 1916, 5 pp. [Received 19th December 1917.] 



Some specimens of thrips from fruit trees in the Crimea in the 

 summer of 1912 were identified as the American species, Taeniotlirips 

 (Euthrips) pyri, Daniel. The author is of opinion that this species 

 should be placed in the genus Physothrips, Karny, and further points 

 out that it is a synonym of T. inconsequens, Uzel [see this Review, 

 Ser. A, V, p. 68]. Only females were found in the Crimea, and for the 

 present it is still doubtful how far it must be considered a pest of 

 pear trees. 



