INTRODUCTION 19 



country, an approximate valuation of the livestock in 

 Great Britain alone amounts to 450,000,000, whilst the 

 area under crops of all descriptions is probably 32,000,000 

 acres. Every insect that is injurious to stock or crops is 

 a factor, and a serious one, on the debit side of " the one 

 industry that never dies." The damage occasioned by 

 what may be termed agricultural insects is often not fully 

 realised by the farmer himself ; but doubly true to-day is 

 the statement made more than fifty years ago by John 

 Curtis in his Farm Insects, when lie wrote : " They (in- 

 sects) annually consume an amount of produce that sets 

 calculation at defiance ; and indeed if an approximation 

 could be made to the quantity thus destroyed, the world 

 would remain sceptical of the results obtained, considering 

 it too marvellous to be received as truth." 



How insects control the destinies of nations, how they 

 render some of the fairest parts of the earth nigh unin- 

 habitable, is perhaps not fully realised by the man in the 

 street, who is apt to consider the insect world too insignifi- 

 cant and unimportant to concern him very much. But 

 unity is strength, and the fact remains that insects and 

 insects alone have held up great engineering schemes, and 

 have been the cause of the abandonment, temporarily at 

 any rate, of undertakings of world-wide importance. Even 

 our homes are not free from the attentions of this tirelessly 

 industrious underworld. Countless hosts of insects seek 

 their livelihood on man himself, in and about his dwellings, 

 his food, furniture, and clothing, whilst even his drugs and 

 cigars pay toll to this insidious foe. 



Not every insect, however, must be considered in the 

 light of a potential enemy, far from it. Honey bees which 

 give us honey, silkworms which spin our silk, lac insects 

 from whose excretions we prepare shellac and sealing-wax, 

 are cases in point. Add to these a number of insects that 

 destroy noxious plants, act as scavengers, work the soil, 

 carry pollen and provide food for mankind, and others 



