320 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



insects are to a great extent dependent on light and heat, and that they 

 are actuated by them and not by any volition of their own. For instance, 

 to explain why a moth flies to a light, it is suggested that the light 

 shining on one side of the insect causes it to turn until both sides are 

 acted upon equally (much in the same way as the vane of a weathercock 

 is acted upon by the wind) and, this action being kept up, the insect when 

 it flies is bound to fly straight to the light, and that insects which move 

 rapidly like moths " get into the flame before the heat of the flame has 

 time to check them in their flight." Why the heat should check them is 

 not mentioned. The common daddy-long-legs will fly into a flame over 

 and over again and it cannot be considered a rapid mover. In fact, it is 

 sometimes hardly out of the flame before it is in again, so that the light 

 can hardly have time to act in the manner suggested. I cannot but think 

 that the views expressed in this chapter under the head of " Tropisms " 

 are in many cases very fallacious. The second and third heads, on 

 instinct and intelligence respectively, are very interesting. It is, however, 

 difficult to reconcile some of the statements in them with the theories 

 previously mentioned under "tropisms." The last chapter (on "insects 

 in relation to man ") deals chiefly with organisations formed and the 

 means taken for the destruction of insect pests. There is a very extensive 

 bibliography occupying 57 pages, the works mentioned in it are arranged 

 primarily in subjects, and then chronologically. This plan has its merits, 

 but it renders it difficult to find a book if you do not quite realise under 

 which heading you should look for it. There is also a very full index. 

 This is one of the most interesting books on entomology in general which 

 has been published for some years. 



"Tree Planting in Natal." By T. R. Sim. 8vo., 354 + xviii pp. 

 (Davis & Sons, Pieter Maritzburg.) 2s. Qd. 



This is an interesting and well-written book on the trees suitable 

 for the different districts of Natal, their propagation and general 

 characteristics. There are twenty-six chapters, with over 100 well* 

 executed illustrations of matter contained in the text. The articles 

 on "The Care of Plantations," "The Planting of Trees," and "Urban 

 and Suburban Horticulture " are full of useful information, and, 

 though primarily intended for dwellers in Natal, might be read with 

 advantage by horticulturists in any part of the world. Although not very 

 comprehensive, the list of indigenous trees is of particular interest, and 

 includes several genera that are commonly cultivated in this country, 

 though the species and varieties are quite distinct. The black wattle 

 industry is the most profitable of any carried out in the Natal forests, 

 although considerable knowledge of how to remove and harvest the bark 

 is required, and it is on record that many planters make reasonable 

 fortunes within one decade and reap returns on expenditure that are 

 probably unequalled in forest management. 



"Timber and Timber Trees." P>y the late Thomas Laslett. Edited by 

 Professor Marshall Ward. 8vo., 442 pp. (Macmillan, London.) 8s. Gd* 



This valuable work, which extends to fully 400 pages, is divided into 

 thirty-seven chapters, with thirty-four well*executed illustrations, every 



