6 



BULLETIN 609, U. S. DEPARTMENT OF AGRICULTURE. 



drawn completely over and fastened down with the shorter bands of 

 silk. The precise process of this species has not been noted in detail. 

 Mr. High has found that the larva when young eats small irregular 

 holes in the leaf, but later consumes more of the leaf as the larva in- 

 creases in size, in extreme cases devouring all of the leaf except the 

 larger veins and midrib. The shelters and the injury to the leaves, 

 due to the feeding of the larvae, are shown in figure 4. 



Fig. 4. — Sweet-potato vine showing work of sweet-potato leaf-folder. (Original.) 



When the shelters are broken open and the larvae disturbed they 

 throw themselves rapidly about, much as a fish does when removed 

 from water, and this violent action soon results in their reaching the 

 surface of the soil, where, if there is a heavy growth of vines, they 

 are difficult to find. 



LENGTH OF LARVA STAGES. 



The number of molts the larva? undergo may vary, but the usual 

 number apparently is 6. In the insectary at Baton Eouge during 

 1916 2 lots of adults were reared from eggs that had been laid by 



