316 HOMES WITHOUT HANDS. 



dividing it into ten parts, and, in consequence, by taking up a 

 considerable time in lifting the separate parts. 



Again, in tbe silken bands which hold the rolled and elastic 

 leaf in its place, we have an excellent example of accumulated • 

 power ; neither of the threads being alone capable of enduring 

 the tension, but their united strength being more than sufficient 

 for the task. 



As soon as the caterpillar has entered its new home, it begins 

 to feed, eating the green substance of the leaf, and generally leav- 

 ing the nervures untouched. Sometimes the caterpillar lives for 

 so short a time that a single leaf is sufficient for its subsistence ; 

 but there are some species which are obliged to repeat the task 

 more than once. 



There are other insects which also make their habitations in 

 leaves ; but, instead of rolling up the leaf and living inside the 

 cylinder, they make their way between the two membranes, and 

 there remain until they have undergone their transformation. 



The reader must often have seen the leaves of garden plants 

 and trees, especially those of the rose, traversed by pale winding 

 marks, that look something like the rivers upon a map, and hav- 

 ing mostly a narrow dark line running exactly along the middle. 

 These curious marks are the tracks which are made by the various 

 leaf-mining insects, while eating their way through the leaf in 

 which they pass their larval state. In most cases, when tbe in- 

 sect has completed its term of larval existence, one end of the 

 track is found to be greatly widened, and to contain either the 

 pupa itself or its empty case. 



The track differs considerably in shape, according to the insect 

 which makes it. Sometimes it winds about in the middle of the 

 leaf, crossing itself more than once in its progress. Sometimes it 

 proceeds in a nearly straight line across the leaf, and very fre- 

 quently, especially in deeply-cut leaves, it follows the outline, 

 keeping to the edge, and not trenching at all on the, central por- 

 tions. 



Insects belonging to three orders are known to make these cu- 

 rious habitations, namely, the Lepidoptera, the Coleoptera, and the 

 Diptera. Of these, the Lepidoptera are by far the most numer- 

 ous and belong to that group which is called, on account of their 

 very minute dimensions, the Micro-Lepidoptera. These are all 

 little moths, so small that on the wing they can scarcely be rec- 



