522 



HOMES WITHOUT HAKDS. 



are allowed to grow, and examining them carefully about the 

 stems and roots. Nothing is more common than to find the 

 stems of thistles swollen in parts, and in many cases the root is 

 affected as well as the stem. Fortunately for the gardener, who 

 hates thistles, even though he should be a Scotchman, as is so 

 often the case with skilled gardeners, the larva of the Cleonus 

 feeds on the juices of the plant at the expense of its life, so that 

 the thistle dies just before the seed is developed, and a farther 

 extension of the plant is thereby prevented. 



There are also gall-making insects among the Diptera. Such, 

 for example, is the Thistle-gall Fly {Urophora CarcZm"), which 

 produces large and hard woody galls upon the thistle, as well as 

 several species of the larger genus Tephritis, some species of 

 which live in the parts of fructification of several flowers, the 

 common dandelion being infested by them. 



"We may now describe, at fuller length than has hitherto been 

 done, another group of insects, which live between the membranes 

 of leaves, and which belong to different orders. 



Leaf Miners and Rollers. 



If the reader will carefully examine the leaves of any rose-tree 

 which grows in the oJDen air, he will certainly remark that many 

 of them are notable for certain curious markings, which look 



