Mining Caterpillars. 



253 



portion of the inner leaf from which the caterpillar has 

 eaten the pulp (parenchyma), while the river itself has been 

 formed by the liquid ejectamenta of the insect, the watery 

 part becoming evaporated. In other species of 



Leaf of the Monthly Rose (Rose Indicd), mined by Caterpillars of Argyromiges ? 



however, the dung is hard and dry, and consequently these 

 only exhibit the valley without the river (see p. 255). 



On looking at the back of the leaf, where the winding 

 line begins, we uniformly find the shell of the very minute egg 

 from which the caterpillar has been hatched, and hence 

 perceive that it digs into the leaf the moment it escapes from 

 the egg, without wandering a hair's-breadth from the spot ; as 

 if afraid lest the air should visit it too roughly. The egg is, 

 for the most part, placed upon the mid-rib of the rose-leaf, 

 but sometimes on one of the larger nervures. When once it 

 has got within the leaf, it seems to pursue no certain direc- 

 tion, sometimes working to the centre, sometimes to the 

 circumference, sometimes to the point, and sometimes to the 

 base, and even, occasionally, crossing or keeping parallel to 

 its o\vn previous track, 



The most marvellous circumstance, however, is the 

 minuteness of its workmanship ; for though a rose-leaf is 

 thinner than this paper, the insect finds room to mine a 

 tunnel to live in, and plenty of food, without touching 



