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Transactions. 



mine. The gallery twists and turns, and in its course follows so close against 

 the earlier portions that the partition between them is broken down, and 

 finall}^ the entire mine appears to form a huge blotch occupying about one- 

 half the leaf-surface. Though thus closely following its former track, it 

 rarely crosses it except under direct need. The midrib forms a barrier, 

 except in its upper and thinner part, where it is invariably crossed.' The 

 final length of the mine may average as much as 26 in. Colour in the 

 early stages white with a fine brown central line occupied by the frass ; 



Fig. 7. 



-Mine of P. panactitorsens in a leaf of Nothopanax arboreum. The dotted 

 line shows the course taken by the larva ; the heavily dotted line is the 

 earliest part of the mine. (Two-thirds natural size.) 



the remainder of the mine, however, is only a shade paler green than the 

 .rest of the leaf, and so is most inconspicuous. The track can be made 

 out by the fine black frass granules strewn in close convex lines across the 

 gallery ; these are quite j)lain on the under-surface of the leaf if looked 

 for, thus demonstrating the extreme thinness of the covering cuticle. There 

 is a narrow portion of the gallery on either side not occupied by frass, so 

 this outer margin is somewhat lighter in colour. The margins of the gallery 

 are regular and even. 



Fig. 8. — Part of track of P. panacitorsens on underside of leaf of Nothopanax Sindairii. 

 Fig. 9.— The same leaf showmg part of mine visible on upper surface. (Natural size.) 



In the case of Nothopanax Sindairii the whole leaf is so mined that 

 the entire under-cuticle can be lifted off. The mine is not conspicuous, 

 but a trained eye can detect the paler colour of the under-cuticle, its 



