GRAPEVINE ROOT WORM 67 



Another ^ inch tube, 10 inches long with 3^ inches vertical and 

 ■6^ inches of its length horizontal was similarly packed and 13 

 grubs placed on the surface of the soil July 29. Four of these 

 had made their way throughout the entire length of the tube by 

 Aug. 3. Another tube 12 inches long, ^ inch in diameter, with 

 2^ inches of its length vertical and the remainder horizontal was 

 filled with tightly packed soil and a number of grubs placed in 

 it Aug. 1. On the 7th one grub had made its way through 7J 

 inches of this tightly packed material. It would seem from the 

 above experiments that while a great many grubs undoubtedly 

 perish in making their way from the vine to the succulent roots 

 on which they feed, they are capable of overcoming great 

 obstacles, and the facts ascertained above at least raise a ques- 

 tion as to the advisability of attempting to interpose barriers 

 between the grub and the roots on which it feeds. 



The young larvae or grubs are undoubtedly able to exist for 

 some time without food. They soon make their way when pos- 

 sible to the young feeding roots where they may sometimes be 

 found in Considerable numbers. The writer, the middle of 

 last August, succeeded in finding eight of these little creatures 

 under a small bunch of feeding roots. They were less than one 

 ■quarter grown and under larger roots near them several others 

 were found which v'ere about half grown. The occurrence of 

 •few half grown larvae and of considerable numbers of nearly 

 full grown individuals the middle of September indicates that 

 these creatures develop very rapidly after they have found 

 suitable roots on which to feed. The finding of a small grub 

 scarcely \\ inch long July 2 indicates that some do not attain 

 their full growth in the fall, since this individual could not have 

 hatched from an egg laid in 1902, as the beetles had hardly 

 begun to appear, and that such individuals must feed to some 



extent in the spring. It seems probable that these very small 



* 



grubs produce the beetles which emerge late in the summer, and 

 are therefore responsible for the very extended period during 

 which adults are found abroad. Most of the grubs complete or 

 nearly complete their growth in the early fall, and on the 



