58 INSECT ARTIZANS AND THEIR WORK 



and as its fore legs are not modified for digging like 

 those of the Mole Cricket, it is compelled to do its 

 tunnelling with its jaws. 



There is another group of Miners to whom 

 reference should be made, although they mine 

 not in the earth, but in vegetable substances. One 

 portion of these we have dealt with in a later 

 chapter as Carpenters, but there are others known 

 as Leaf-miners, who spend their larval existence 

 in making tortuous burrows in the soft cellular 

 tissue {'parenchyma) of green leaves. The larvae 

 that get a living by this industry are not confined 

 to one natural order ; in their perfect state they 

 are moths, flies, and beetles. They can hardly be 

 classed among insect pests, for as a rule they do not 

 destroy a whole leaf, but they cause a good deal 

 of annoyance to some gardeners who are vexed to 

 see even one disfigured leaf on a plant. An excep- 

 tion to this remark should be made in the case of the 

 Celery Fly, whose larva eats so much of the leaf as 

 to seriously affect the storing up of the material 

 that goes to the formation of the firm white base 

 of the leaf-stalks for which the plant is cultivated. 

 Where such depredations do not have serious effect 

 the leaves are those of trees or shrubs. 



The moths whose larvae mine leaves are the most 

 numerous, and when it is stated that in Britain 

 alone we have somewhere about three hundred 

 and fifty species of these Icpidopterous leaf-miners, 

 it will be seen that it is impossible in this place to 

 do more than mention a few sample species. These 



