67 



Salisbury with a view to deterniiniiig the depth of dry earth that 

 would prevent emergence, it was found that when buried at a depth 

 of 2 inche^^ most of the moths reached the surface, but all in a crippled 

 condition, the wings being shrivelled and the insects unable to fly. 

 When buried at 4 and (> inches all died in the soil without being able 

 to reach the surface. The stalks in the field, therefore would have to 

 be covered with loose earth to a sufficient depth during November 

 and December when the moths are emerging. They would have to 

 be laid along the bottom of the furrows during ploughing, and 

 sufficiently deep to escape being caught and dragged to the surface 

 by the harrow. Certain maize growers have reported success in 

 carrying out these operations, which present less difficulties in the 

 more friable soils. 



SwAiNE (J. M.). Canadian Bark-Beetles. Part II. A Preliminary 

 Classification, with an Account of the Habits and Means of Control. 



—Canada Dept. Agric, Ottawa, Bull. no. 14, 6th September 1918, 

 143 pp., 31 plates. [Received 11th December 1918.] 



The object of this bulletin, of which Part I has previously been noticed 

 [see this Review^ Ser. A, v, p. 399], is to bring together the results 

 of many years' work and to afford a means whereby foresters, students 

 and others may readily identify the species of bark-beetles that are 

 injurious in the Canadian forests. A general account is given of the 

 Hfe-history of the beetles and their habits, the damage they inflict 

 and the means of combating them ; the structural characters are 

 also discussed and a preliminary classification of the identified species 

 is included. There are still numbers of undescribed species occurring 

 in Canada. It is pointed out that at the present time the protection 

 and correct utilisation of the timber resources of Canada is of greater 

 importance than ever, and the information contained in the present 

 bulletin should be of inestimable value in preventing the continued 

 loss of timber owing to the depredations of insects. A list of coniferous 

 host-trees, a glossary of technical terms, a bibliography, and an index 

 of species are included. 



Davis (J. J.), The Corn Root-Aphis and Methods of Controlling It. — 



U.S. Dept. Agric, Washington, D.C., Farmers' Bull. no. 891, 

 December 1917, 12 pp., 5 figs. [Received 12th December 1918.] 



This bulletin gives a popular account of Aphis maidimdicis (corn 

 root-aphis), its seasonal history and habits, its relations with ants, 

 especially Lasins niger antericatius, and the methods recommended 

 for its control. 



Crosby (C. R.) & Leonard (M. D.). Manual of Vegetable Garden 

 Insects.— iVew' York, The Macmillan Co., 1918, 391 pp., 232 figs., 

 8vo. [Price $ 2.50]. 



This book, one of the series of Rural Manuals edited by L. H. Bailey, 

 gives a great deal of information concerning the principal insects that 

 attack market and vegetable crops in North America. The insects 

 are grouped in sections under the heading of the crops affected. At 

 the end of each is a complete list of the insects injurious to the plants 

 dealt with, with a reference to the page on which the description of 



