190 BRITISH LEPIDOPTEKA. 



EGG-LAYING. The egg is deposited on the underside of an apple- 

 leaf. 



MINE. As soon as the larva is hatched, it mines into the upper 

 layer of the leaf, usually towards the base, forming a slender gallery, 

 which turns pink, and betrays the presence of a larva before it is 

 visible to the naked eye. The gallery is frequently near a vein of the 

 leaf. As the mine becomes wider it changes to an orange-colour, 

 with an irregular track of brownish excrement. It is never very 

 conspicuous from above, but quite invisible on the underside. In the 

 last portion of the mine, the larva doubles back on its previous course, 

 and forms a blotch. The mines are usually more abundant on the 

 lower branches of an apple tree, a 'single leaf sometimes having as 

 many as a dozen larvae in it. Frey writes : " Die Mine im Apfelblatt 

 ist leicht zu erkennen und mit keiner einer anderen hier wohnenden 

 Art zu verwechseln. Sie nimmt als ein ungewohnlich kurzer, feiner 

 Gang meistens mehr in der Mitte des Blattes ihren Ursprung und 

 erweitert sich dann plotzlich zu einem unregelmassig rundlichen 

 Fleck von gelbbrauner Farbe. Die braunen Kothmassen bilden eine 

 etwas breitere Linie " (Linn. Ent., xi., p. 372). Nolcken writes: 

 " Two mines from Heinemann are rust-yellow, in the older parts rust- 

 brown and mostly bounded by the leaf-ribs. At first the mine follows 

 a stronger rib or is tortuous (the windings lying close together, and 

 occupying a small space in the angle of two ribs) ; the frass line is 

 bounded (but not sharply) with pale, often interrupted, narrow margins, 

 and is, in the latter part of the mine, always more broken and 

 irregular, dividing into little heaps of grains towards the end. Here 

 it is probably 2-5 mm. broad, but since it is very much twisted in a 

 short space, it frequently crosses and absorbs an earlier portion of the 

 mine. The larva, too, shows a tendency when feeding to eat the 

 parenchyma for a considerable distance on either side of its head, and 

 this widening of the mine allows the excrement pellets to be arranged 

 in longer curves than can occur in a narrow and more direct mine. 

 The mine occasionally takes on the blotch or blister form, owing to the 

 walls between neighbouring windings being eaten away, but this is by 

 no means uniformly the case." 



LARVA. The larva is orange coloured, with the dorsal vessel 

 slightly darker, the skin shiny, the head pale chestnut (Vaughan). It 

 mines with the dorsum uppermost. 



Cocoox. The cocoons average 2-9 mm. long and 2-1 mm. wide. 

 They are considerably broader at one end than the other, and more 

 flattened at the wide end (giving the idea of the shape of a mussel- 

 shell to the naked eye). The colour varies from orange-brown to 

 deep red-brown. The projecting rim at the wider end is more orange- 

 brown than the raised portion, and is characterised by a number of 

 projecting points, by which the cocoon has evidently been fastened to 

 some object, as silken threads extend therefrom. The surface of the 

 cocoon is covered with minute pits, and its upper surface is domed (not 

 flattened) ; a little white flossy silk is scattered over the surface. 

 [Described June 14th, 1898, under a two-thirds lens, from cocoons 

 sent by Dr. Wood.] Vaughan writes : " The full-fed larva leaves the 

 leaf in which it has fed, by the upper side, and spins its cocoon in a 

 cranny, or on the surface of the ground. The cocoon itself varies in 

 colour, from dark chestnut-brown to bright orange : it is broader at 



