NOTES AND ABSTRACTS 



859 



the bark, and below the buds, in April, and hatch in about three weeks, 

 the larva becoming adult about one month after hatching. There are 

 several broods (four ?) in a year. The mature insect is yellow, then red- 

 dish with black markings : it hibernates in cracks in the bark of the Pear 

 tree. It is preyed upon by the lace-wing fly and the two-spotted lady- 

 bird. The latter part of April is the best time to spray either with 

 kerosene emulsion or with a solution of 1 lb. of soap in 4 gallons of 

 water. — F. J. C. 



Pear Trees, Barren, Inducement of Fruit-bud Formation. 



By Geo. Bellair {Rev. Hort. pp. 42-43, Jan. 16, 1904 ; 1 woodcut).— An 

 interesting article on inducing the formation of fruit-buds by successive 

 suppression of other buds and consequent concentration of sap vigour. 

 Woodcuts illustrate process. — C. T. D. 



Pentstemon, Nectaries Of. By Prof. Dr. E. Loew (Berlin) (Beih. 

 Bot. Cent. xvii. pp. 85-88).— The formation of nectaries is not the same 

 in the different species of Pentstemon, for in those species of the group 

 Fruticosi examined there are no honey glands on the filaments, whilst 

 in others they are on the bases of the upper filaments. The staminode in 

 the former assists in the protection of the honey. — G. E. S.-E. 



Phaius Blumei Bernaysii. By R. A. Rolfe (Orch. Bev. vol. xii. 

 p. 91). — Introductory and historical particulars are appended of this 

 distinct yellow-flowered variety of the species. — H. J. C. 



Photographs taken in the Dark. By Dr. Russell (Gard. Chron. 

 No. 935, p. 370, figs. 165 and 166; Nov. 26, 1904).— At a recent 

 meeting of the Scientific Committee of the Royal Horticultural Society 

 Dr. Russell exhibited some photographs of sections of wood which he had 

 taken in the dark, showing that almost all woods have the property of 

 acting on a photographic plate in the dark. Some woods, however, 

 require a much longer time to produce a good picture than others ; the 

 time varies from half an hour to eighteen hours. The definition of the 

 rings and structure of the wood in the photographs are most charming. 

 Apparently it is only the light- coloured rings in the Scotch Fir that act 

 on the plate, the dark ones having no action. In the Larch, on the 

 contrary, the dark rings are the most active. — G. S. S. 



Phototaxis and Culture Drops, Physical Properties of. By V. 



Chmielevsky (Beih. Bot. Cent. xvi. pp. 53-66, with one plate). — Discusses 

 the manner in which light is reflected in the drops used for hanging- 

 drop cultures, and points out that the results in such cultures, as regards 

 phototaxis, are entirely contrary to what most authors have supposed, 

 the supposed negative phototaxis being really positive phototaxis. 



G. F. S.-E. 



Phrygllanthus aphyllus (Loranthaceae), Structure and Bio- 

 logy of. By K. Reiche (Flora, xciii. 1904, pp. 271-297 ; t. v. and 

 9 cuts). — This interesting parasite occurs in Chile, Peru, and Argentina : 

 it infests Cereus chiloensis and other species of the genus, from the sides of 

 which it projects to form a tuft of branches, brilliant red at the young 



