172 



HARDWICKE'S SCIENCE-GOSSIP. 



[Aug. 1, 1867. 



the pupa state in the autumn, remain unchanged till 

 the following May; and many a fallen brown leaf, 

 blown hither and thither by every gust of winter's 

 wind, contains within it one of these living pupae, 

 destined to appear in the ensuing May, as one of 



Fig. ];6. Mined Oak Leaf, and Larva of Coriscium 

 Brongniardellum, enlarged. 



the most elegantly and delicately marked of our 

 native small moths. There are several species which 

 mine the leaves of the oak in the way described, but 

 they all belong to the genus LitJwcolletis (fig. 177). 

 When the month of October is 'well advanced 

 and the leaves of the oak are fast turning brown, 

 one very small mining larva will sometimes produce 

 a very singular effect. It commences a very narrow 

 slender gallery close to the midrib, and then, after 

 proceeding a short distance in one direction, turns 

 sharp round, so as to form the continuation of its 

 mine in close proximity to the part already mined; 



by repeated turns, it thus eventually forms a small 

 blotch close to the midrib, the larva as it proceeds 

 getting gradually farther and farther away from the 

 midrib. It thus completely separates the part of 

 the leaf immediately beyond its mine from any con- 

 nection with the midrib, and one singular effect 



Fig. 177. Oak Leaf mined by Lithocolletis. 



thereby produced is, that whilst the remainder of 

 the leaf becomes brown, the part towards which the 



Fig. 178. Mined Oak Leaf, and Larva of Nepticula sub- 

 bimaculella, enlarged. 



larva is mining continues green ; and by these green 

 blotches on the leaves we often readily detect the 

 presence of the larva, which is of a very pale green, 

 with a pale brown head. When full-fed, it quits the 



