190 HALF-HOURS IN THE GREEN LANES. 



markings thus left on leaves when we know that in 

 this country we have several hundred species of 

 the larva of tiny moths alone that are engaged in 

 this operation ! Look at the leaves of any young 

 oak-tree in June, and you will find that some of 

 them have heen mined nearly one half their area, so 

 that nothing has been left except the two thin skins 

 of the upper and lower sides of the leaf. The larva 

 that has done this has no legs. Its whole specialisa- 

 tion seems to have been concentrated in its jaws, 

 which are constantly at work devouring the green 

 parts of the leaf the chlorophyl. When full fed 

 this species of larva descends to the ground by 

 means of a spider-like thread, and forms a cocoon in 

 the ground, where it stays till the coming May. In 

 that month you may see the tiny moths, of which it 

 forms one, sporting on and about the leaves of the 

 oak. It is about half an inch in the expanse of its 

 wings, which are of a pale golden green colour. 

 This species goes by the name of Micropteryx 

 subpurpuretta. We have other English species of 

 this genus that are similarly devoted to leaf-mining, 

 some of them in the leaves of the birch. July, 

 however, is the month when oak leaves are most 

 discoloured and marked by the insect leaf-miners. 

 One species of insect whose larva is then at work 

 (Coriscium Irogniardellum, Fig. 133) is an elegant 

 little moth, about a third of an inch across its wings. 

 The fore-wings are of a glossy brown, ornamented 

 with four oblique spots running from the edges. 



