568 



NA TURE 



[October i i , i 894 



he goes into rather more detail concerning insects. 

 Knowledge of the inner life of animals is most desir- 

 able, and shoald be spread through the whole of the 

 country districts by the Technical Education Committees 

 of County Councils, by means of competent lecturers, 

 in the absence of any standard text-book on the subject. 

 There is a capital book on Agricultural Zoology in 

 France, compiled by Dr. Brocchi, entitled " Traite 

 de Zoologie .Agricole," in which detailed descriptions are 

 given of all the animals that are useful and in- 

 jurious to cultivators. Their habits {inccurs) are first 

 detailed, then their use {utili/c), or the harm (^dt'gals) 

 occasioned by them, so that one may see at a glance 

 those that may be counted upon as friends or foes. It 

 might be supposed naturally that in a treatise upon 

 Agricultural Zoology, Dr. Ritzema Bos would have 

 dealt at some length with, for instance, such a 

 useful bird as the kestrel {Falco tinnunculus), which 

 must be held to be one of the best friends 

 of the farmer, for it feeds upon mice, rats, and 

 cockchafer?. Sivallows, martins, and swifts are dismissed 

 with exceedingly short notices, and their indescribably 

 good services to cultivators are unfairly depreciated in 

 the following inconsistent passage : — 



" Swallows fly quickly and catch insects while on the 

 wing. The insects on which they prey are generally unim- 

 portant to agriculture and forestry ; but they may also do 

 good by catching crane-flies (Tipula) and ribbon-footed 

 corn-flies (Chlorops), which often fly about our fields in 

 enormous swarms in order to lay their eggs." 



It must be strenuously denied that the insects on which 

 they prey are unimportant to agriculture, as they are 

 known to be especially fond of aphides, and many hop- 

 planters believe that the far greater frequency of the 

 attacks of the Phorodon (aphis) huinitli upon hop-plants 

 in the last five years is due in a degree to the scarcity of 

 swallows and martins. There is no doubt, also, that 

 these birds clear off the Hessian fly, Cecidomyia tritici, 

 and others of the Cecidomyidir, and as they live entirely 

 on insects, and especially on the smaller and most 

 dangerous insects, they are of inestimable benefit, 

 and should therefore be preserved with religious care. 

 It is much to be lamented that swallows, martins, 

 and swifts are so ruthlessly massacred in the simny 

 climes in which they pass the winter seasons. Plovers, 

 too, whose value to farmers is inestimable, are not 

 alluded to. This is an unfortunate omission, as it is 

 desirable to clearly point out that these birds should be 

 encouraged, and that the general raids upon their eggs, 

 to satisfy the appetites of gourmets, should be stopped. 



In his large, valuable work, " Tierische Schadlinge 

 und Niitzlinge fiir Ackerbau, Viehzucht, Wald- und 

 Gartenbau," published at Berlin in 1891, Dr. Ritzema 

 Bos, like Dr. Brocchi, gives full accounts of all animals 

 in any way connected with the field, forest, and garden, 

 and this might have been liberally epitomised and trans- 

 lated for the benefit of British agriculturists with far 

 more advantage to them than the unsatisfactory ri'chauff'i'e 

 now before us. Insects are Dr. Ritzema Bos's strong 

 point, as all arc aware who know his labours in this 

 direction, so that it is not surprising to find consider- 

 ably more than a third of the contents of " .\gricultural 

 Zoology" devoted to them. But it is rather strange 

 NO. I 302. VOL. 50] 



that some very import.int insects are not mentioned, and 

 that others are dismissed with a short account of their 

 habits. In some cases methods of prevention and remedies 

 against insect attacks are suggested, but they are generally 

 given in the briefest possible manner. Thus for the 

 pea-weevil {Sitoiics Uncatus) the remedy prescribed is 

 " rational rotation," which will convey little or no meaning 

 to the perplexed pea-grower. 



For the ravages of the Diamond-back Moth {Pltilella 

 cruciferaruni), no remedy whatever is mentioned, 

 although the caterpillars of this insect occasionally do 

 serious harm to many species of the Brassica, as in 

 1S91, when many thousands of acres of turnips, rape, 

 and cabbages were ruined by their action. 



Another instance of a curious remedy may be given 

 in the paragraph upon Cockchafers {Mdolonihavulgaris) 

 in which it is recommended that the grubs that are 

 turned up during ploughing should be collected, and 

 that the cockchafers should be caught. " This is very 

 expensive, since it has to be done very energetically if 

 most of them have left the pupa cas?. A part of the 

 expense may, however, be recouped by using the cock- 

 chafers as manure." This " part of the expense," it is 

 thought, would be absurdly infinitesimal. 



Again, for the Red Spider {Telranychits ielarius), 

 most destructive to many crops of the firm, garden, and 

 glass-house, no modes of prevention or remedial mea- 

 sures are hinted at, although economic entomologists 

 have pointed out that as moisture is most obnoxious to 

 these mites, washing or spraying infested plants fre- 

 quently is an efficacious remedy against them. One 

 of the best parts of this volume is that devoted to 

 the Ani^uillulida:, or eelwornis, which are most injurious 

 to a number of crops, and in many cases are quite 

 unsuspected enemies. 



With regard to the insects omitted, it will be seen that 

 none that are injurious to fruit crops have been included, 

 though fruit-growing forms an important feature of 

 British land culture. As in Holland and Germany, the 

 Winter Moth (Cheimatobii bnimatd) is terribly destruc- 

 tive to the apple crops in this country, and the Codlin 

 .Moth {Ciiipocapsa poinonclla) is almost equally injurious 

 in some seasons to apple-trees in (ircat Britain, the Con- 

 tinent, and the United States and C uiada. Both these 

 are unnoticed, as well as several other moths, and many 

 weevils and sawflies, that attack apple, pear, and 

 plum trees, gooseberry and currant bushes, and rasp- 

 berry-canes, against whose onslaughts fruit-growers would 

 only be too thankful to have some practical advice from 

 an expert of the reputation of Dr. Ritzema Bos. 



In ;i few instances valuable remedies are recommended 

 against insects, as, for example, the remedy adopted for 

 the Silver Y }>loth(P/usia j^ti/niita), by fastening together 

 by laths several long troughs with steep inner walls, 

 at distances equal to those between the adjacent 

 furrows, and the caterpillars are swept by besoms fixed 

 to the laths into the troughs, from which they are 

 collected in sacks at the end of the furrows. With 

 this cheap machine about twelve acres per day can be 

 cleared. This is a practical remedy, and is derived from 

 Taschenberg, the most practical and able of all economic 

 entomologists, who has done more for cultivators in the 

 way of describing insects, and prescribing methods of 



