308 



HALF HOUKS WITH INSECTS. 



[Packard. 



prey. The construction of their nests does not require so 

 much intelligence as is shown by the ant lion. The larva 

 is a hideous being, with a large horn on its back, by which 

 it is enabled to prop itself up in its hole. 



None of the flies are architects. Some involuntarily form 

 galls of various shapes, in which the maggots are domiciled. 

 For example, the gall-fly of the willow forms the familiar 

 pine-cone-like swelling (Fig. 239) found on willow twigs, 

 while another kind forms a mass of willow leaves like the 

 Fig. 239. 



Willinv gall. Cabbnge willow gall. 



sprouts on a cabbage (Fig. 240). The many-chambered gall 

 of the gall-gnat of the grape vine is represented by figure 

 241 (this and the two preceding figures from Riley), and 

 Mr. Riley has delineated the filbert gall which grows in large 

 masses on the grape vine (Fig. 242, representing a mass of 

 them of the natural size). 



Among the caterpillars of the moths are many of the 

 smaller kinds which mine the leaves of plants, or tunnel the 

 stems ; others, more skilful, cut out portions of leaves and 



20 



