672 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Fab.) is the most serious sugar-cane pest that the planter in Louisiana 

 has to contend with. 



It destroys the eyes of seed-cane, thereby reducing the stand 

 during the following year; stunts the growth of the caues; and by 

 tunnelling and girdling them makes them an easy prey to high winds. 

 Also, the holes made by the borer are the means of entry for the 

 various fungous diseases to which sugar-canes are addicted. 



Investigations of methods of control are now being made, the 

 results of which will be published in due time. — V. G. J. 



Sugar Cane Insects of Hawaii, The. By D. L. Van Dine 

 (U.S.A. Dep. Agr., Bur. Entoni., Bull. 93; June 1911; 4 plates, 

 4 figs.). — Among the sugar-cane insects discussed in this Bulletin are; 

 (1) The sugar-cane leaf-hopper (Perkinsiella saccharicida) ; (2) the 

 sugar-cane leaf-roller (Omiodes accepta) ; and (3) the sugar-cane mealy- 

 bug (Pseudococcus calceolariae). Their life-histories and the best means 

 of extermination are described in detail. — V. G.J. 



Sugar Cane, Selection and Hybridization of the. By 



Lewton-Brain [We^st Indian Bull. vol. iv. p. 63 ; see vol. xi. No. 4, 

 p. 338). — An account of most interesting experiments conducted along 

 the lines of Mendel's laws, with the object of improving the tonnage 

 of cane to the acre, the sugar-content of the juice, and the power of 

 resistance to disease. — G. H. L. 



Symbiosis and Parasites, Chemistry of. By Dr. Julius Zell- 

 ner {Beth. Bot. Cent, Bd. 28, pp. 473-486).— The author gives a 

 short sketch of the most recent discoveries in the theory of symbiosis. 

 - He then compares the chemical contents (fats, carbohydrates, cell-wall, 

 proteins, ferments, bases, acids, colouring matters, ash) of host and 

 guest, or of the two partners in symbiosis. Thus he gives these contents 

 for algae, fungi, and lichens, for rye and ergot, for maize and Ustilago 

 Maydis, for Trametes and willow, Viscum and its hosts, &c. 



He lays stress on the great differences which occur between the 

 cell-contents of the two forms. He finds that in lichens colouring 

 matters occur for which it is difficult to find the chemical origin in 

 either alga, or fungus. Very few substances seem to pass without 

 change from the host into the guest plant. The enzymes found in the 

 parasite or saprophyte depend upon the chemical constitution of the 

 host. The ash of the mistletoe differs from that of the wood and bark 

 on which it grows, and bears more resemblance to that of the leaves 

 of the particular tree. There are other interesting points in the paper 

 regarding parasitism, phagocytosis, &c- — G. F. S. E. 



Tannin Contents and Starch in Trees. By August Eenvall 

 (Beih. Bot. Cent. Bd. 28, pp. 282-306).— The author has examined 

 the contents in tannin material (reaction to bichromate of potash) in 

 buds, bark, wood, pith, &c., of twenty-two trees and shrubs [Acer 

 spp., horse-chestnut, lime, birch, beech, Syringa, &c.), both in 



