222 The Museum Gazette 



41 In the month of June we may frequently find on young oak-bushes 

 that many of the leaves have extensive mines, occupying nearly a 

 third of the leaf, and the part mined is so completely cleaned out that 

 nothing is left but the two skins of the leaf, and it hence has a very 

 flimsy appearance ; on holding one of these mined leaves up to the 

 light, we should perceive within it a mass of short, dark grey thread- 

 like substances, being the excrement of the larva ; possibly in some 

 of the leaves we might succeed in finding the larva still there, a dull 



whitish creature, with no legs, but with a well defined head, his jaws 

 being kept constantly at work devouring the green portion of the 

 leaf, which imparts a greenish tinge to the dorsal vessel running 

 along the centre of its body. This larva, when full fed, quits the 

 leaf and descends to the ground, which it enters, and there spins 

 a subterranean cocoon, coated with particles of earth; within this 

 cocoon it changes to the pupa state, and it is not till the following 

 May that the imprisoned moth makes its escape and delights to fly 

 round the oak twigs in the sunshine. It is a pretty glossy creature, 

 about half an inch in the expanse of the wings ; the fore-wings are 

 of a pale golden green, with a faint appearance of two paler spots, 

 one on the inner margin beyond the middle the other midway 



