26 BULLETIN 730, U. S. DEPARTMENT OF AGRICULTURE. 



grape cane or weed stem, pausing every few inches to deposit an egg. 

 No attempt is made to conceal the eggs , except that the moth occasion- 

 ally will move along the margin of a leaf and bend her abdomen 

 over the edge, placing eggs on the underside. The eggs are attached 

 very feebly, and the rain or wind soon dislodges them and they fall 

 to the ground before hatching. One female kept in a cage produced 

 555 eggs and several others more than 400 each. About a week is 

 required by the female in which to deposit her quota of eggs. Fe- 

 males caught in the vineyard while ovipositing and placed in bottles 

 continued to drop eggs with scarcely any intermission resulting from 

 the changed conditions. 



As has already been mentioned, there is a close resemblance in the 

 moths to the comb-building wasps of the genus Polistes. The gravid 

 females are somewhat more deliberate in flight than are the wasps, 

 but the males dart about on the wing in a maimer that is very wasp- 

 like. The males have a habit of resting for long periods in exposed 

 positions about the vines, and when approached or disturbed fre- 

 quently flutter their wings rapidly, giving off a buzzing sound that 

 still further increases their resemblance to wasps. Karely the 

 female also will engage in this buzzing performance. 



Bottles in which females had been kept in the insectary, and in 



which they had been seen to elevate their genitalia, were several 



times taken to the vineyard after the females had been removed. 



"When uncorked, males would appear almost immediately, evidently 



attracted by the scent, and would even enter the bottles in search of 



the females. 



LARVAL ACTIVITIES. 



The larvae hatch from eggs that at the time are almost invariably 

 scattered over the ground in the vicinity of grapevines. After 

 hatching they at once burrow into the soil and attack the larger 

 grape roots whenever found. It is possible that they subsist on 

 small roots and root fibers while searching for their permanent places 

 of attack, but undoubtedly many of them perish before finding roots 

 to their liking. They enter the roots wherever they come in contact 

 with them, either- close to the vine or far out toward the extremities. 

 In one case a larva was found that had penetrated a foot of stiff clay 

 soil and attacked a root at a point 19 feet from the vine. 



The ability of the larvae to penetrate the ground to a considerable 

 distance was shown by placing a large number of hatching "eggs on the 

 surface of soil that had been placed to a depth of 9 inches over 

 some sections of grape root in the bottom of a wooden box. Twenty 

 days later the grape roots were removed and the bark found to be 

 filled with young borers. The borers had mined an inch or more in 

 the bark, some of the burrows encircling the roots and others ex- 

 tending parallel with the grain of the wood. 



