COMMON VAPOURER MOTH 181 



of all the important facts as to their lives and habits. It is not 

 beyond the powers of school children to study the life-histories 

 of a few of the commoner noxious insects, and such a study, if 

 carried out with thoroughness on some of those which are quite 

 common, can be made highly instructive and interesting. An 

 investigation can, for instance, be made of the life-history of the 

 common winter moth ; and this, if completely carried out, 

 establishes a sort of type in the mind of the young observer. 

 The life-histories of fungi involve the use of the microscope, and 

 is not so suitable a subject for school study, although it is desirable 

 to encourage the young students to look for blotches and dis- 

 colorations on leaves and shoots. These are frequently attributed 

 by gardeners and farmers to frost and cutting winds, when they 

 are, in fact, the outcome of attacks by fungi or aphides. 



Prevention is better than cure, and fortunately there are a 



FIG. 73. Common Vapourer Moth, with Caterpillar and wingless 

 female Moth. 



number of ways in which attacks may be forestalled. For 

 example, if the soil is turned up in the autumn, any insect larvae 

 or pupae, which may be buried in it, will be exposed to the 

 weather and killed, or will be eaten by the birds. Insectivorous 

 birds, such as the titmouse or the starling, should therefore 

 be encouraged. Again, although fungi and insects can usually 

 maintain themselves on more than one species of- plant, the 

 chances are that if ground occupied one summer with a given 

 species of plant is occupied the following summer with a different 

 species, or, better still, with a plant belonging to a different order, 

 the insect or fungus which throve on the former will be starved 

 out by the latter. Hence regular change of cropping is necessary. 

 Crops, which owing to bad tillage, unfavourable weather, or 

 poverty of soil, are not growing vigorously, are not in a position 

 to resist the attack of fungi, and crops in the seedling stage are 

 also very frequently the victims of attack. 



