226 Miss A. L. Embleton on the 



Abroad, however, and particularly in the United States, 

 this problem of the natural enemies of insect-pests is 

 receiving attention and careful stud}'. In a paper* just 

 come to hand, Mr. H. Maxwell-Lefroy remarks that, beyond 

 useful birds and other animals, " there are the hosts of pre- 

 daeoous and parasitic insects of whose work it is difficult to 

 form any conception. Little can be done to encourage 

 these beyond taking reasonable precautions that our pre- 

 ventive or remedial measures do not destroy them, and 

 spreading such a knowledge of them as will prevent their 

 destruction through ignorance as pests." 



It is very satisfactory to find from such notes as this and 

 that of Mr. Johnson, that Economic Entomologists are recog- 

 nizing that their operations must not be confined to mere 

 destruction ; and that to be of permanent value they must 

 be based on a reliable knowledge of the natural history of 

 the pests. 



In connection with this it may be remarked that a 

 knowledge of the natural modes of dissemination of both 

 the pests and their parasites is essential in the work which 

 is carried on in various parts of the world to prevent the 

 introduction of pests, and often spoken of as quarantine. 

 These regulations exist in Austria-Hungary, Belgium, 

 France, Germany, Canada, British Columbia, Cape of Good 

 Hope and elsewhere, thougli not in Britain. 



It is indeed difficult to understand how insects that are 

 not only apterous but which have, in many cases, even lost 

 their legs, become so widely distributed, or even how they 

 succeed in spreading from tree to tree. All Coccidm, how- 

 ever, have the power of walki-ng when newly hatched, I 

 have watched the active young of several species — Lecaninm, 

 various spp., and Ftilcinaria caiiu'llicola — and I found tliat 

 'they wandered restlessly about on the plant, and in a very 

 short time I noticed they were migrating from the plant, 

 so that out of the myriads which appeared only a few 

 remained on the host plant. These, however, are quite 

 sufficient to carry on the destruction of that plant, though 

 the majority wander off in search of new hosts. I carried on 

 experiments in this matter on scales on camellia and rose- 

 plants, grape vines, ferns, and other plants, and the result 

 was always that the majority of the young wandered away 

 in spite of all obstacles. It is known that considerable 



* " Sugge.stions for Insect Control in the "West Indies." West 

 Indian Bull., ii, No. 4, pp. 318-344. 



