44 ASSOCIATION OF ECONOMIC ENTOMOLOGISTS. 



into the choke-cherry bushes (PL I, fig. 2) was quite comparable to 

 the exit from the walnut trees. The worms first built large nests 

 at the base of the bushes, with considerable web upon the ground, 

 and then advanced upward from night to night. Many of these 

 nests were of the kind described above — that is, composed of parallel 

 sheets of silk. 



The migration to the hackberry was not so striking as that to the 

 choke-cherry bushes, but was even more interesting. At first the 

 worms congregated in temporary webs in the crotches of the larger 

 limbs, but they gradually advanced upward from day to day and 

 built webs in the smaller branches. I first observed the worms trav- 

 eling up the hackberry tree at 5 p. m. of August 3. I found a few 

 worms climbing up the large tree and two webs with worms in the 

 first and second large crotches about 7 and 10 feet above ground, 

 respectively. There were also a few worms climbing up one of the 

 main ascending limbs about 20 feet above ground. There was no 

 web spun about the base of the tree, but the caterpillars observed 20 

 feet above ground had some web spun upon the limb. This latter 

 web, as also the number of worms within it, increased from day to 

 day until it extended about 8 feet in length and surrounded the 

 greater part of the limb, which was perhaps 7 inches in diameter and 

 free from smaller limbs. This web was apparently not a resting 

 place, but mainly a route of travel, for the worms seemed to be more 

 or less on the move all the time. The webs in the crotches mentioned, 

 I decided, were resting places for the worms during the day. I 

 think there can be no doubt that the worms in the hackberry came 

 from the walnut trees. Worms were observed upon the ground in 

 the early forenoon headed toward the tree. Again, there were no 

 webs with dead leaves in them; in fact, the tree showed no evidence 

 whatever of having been previously infested, and the worms were of 

 several different sizes. 



The next clay — August 4—1 observed nests upon limbs farther up 

 in the hackberry and fewer caterpillars in the nests in the crotches. 

 I also noticed nests in the very top of the tree among the leaves, which 

 showed evidence of being stripped. Four days later — August 8 — the 

 number of worms in the loAver nests (in the crotches) was rapidly de- 

 creasing, while there were more nests in the top of the tree, which 

 could now be seen from the outside and at some distance. A few 

 worms were seen climbing up the trunk, and a few could still be found 

 in the webs upon the walnut trees. This was also the situation upon 

 the following two days, when I left the Point. 



The condition upon the other hackberry trees mentioned, 50 and 

 100 feet southwest and northeast, respectively, from the walnut trees, 

 was quite comparable to that already described. In the southernmost 

 of the trees just mentioned I observed only a few webs, but all the in- 



