Feb., 1906.] Notes on the Fall Webwcrm in Ohio. 455 



upon a hedge of osage orange, at Berea, Ohio. Closer investiga- 

 tion, however, revealed the fact that the web was not upon the 

 osage orange at all, but upon a small wild cherry tree that grew 

 in the hedge and which had escaped my notice. 



Wahnit Trees. — Only a few walnut trees exist at the Point, 

 but the worms played havoc with these, while of all the great 

 abundance of choke-cherry, onl}" two instances were noted 

 where the infection was at all so extensive. A clump of five 

 walnut trees (each about six inches in diameter), became liter- 

 ally defoliated and about 150 nests were counted upon them. I 

 have observed, however, that the number of webs does not 

 necessaril}^ indicate the number of broods, since a large brood 

 may desert its old nest, and build a new one, or divide and form 

 two new nests. (I use "nest" to distinguish the denser part of 

 the web. See also Other Observations.) 



When food became scarce the worms began to migrate down 

 the trunks of the trees, here and there covering the limbs and 

 trunks with web. This migration occurred chiefly at night, the 

 worms generally resting, as usual during the da}^ in temporar}^ 

 webs frequently located at the base of the trees and of extraor- 

 dinary size. In one instance I estimated that not less than two 

 quarts of worms occupied a certain web. 



In the early part of the forenoon I usually found some strag- 

 glers which had been overtaken by daylight, evidently en route 

 from the trees. Many of these were found dead in small pits, 

 from which, as experiment showed, they had been unable to 

 extricate themselves, and had died from the excessive heat. 



The worms migrated mainly eastward to a clump of choke- 

 cherry nearby and westward to a large hackberry about forty 

 feet distant. This migration continued during about ten days. 

 In four days the number of nests in the choke-cherry bush 

 increased from six to twenty-five and the bush was literally 

 stripped as the worms advanced. 



The migration to the hackberry was not so striking as that 

 to the choke-cherry bush but even more interesting. At first 

 the worms congregated in the crotches of the larger limbs but 

 advanced upward from day to day and formed webs in the 

 smaller branches. They soon began to strip the leaves and the 

 webs could then be seen at some distance from the outside of the 

 tree. 



Mr. W. B. Herms, who remained at the Laboratory until 

 August 31st, was kind enough to observe the worms for me and 

 reported that after my departure the worms migrated only a 

 little farther east into the choke-cherry bushes and became 

 fewer in number. I presume that they were then mature and 

 that they wandered away to pupate. The trees began to show 

 new life and by the time Mr. Herms left were quite green again. 



