OBSERVATIONS ON HABITS OF FALL WEBWORM. 45 



dications were that these came from the walnuts. Upon the northern- 

 most one I found five nests in the forks of the tree, with a few other 

 webs quite at the top. This was on August 8 and only two da}^s be- 

 fore the termination of my observations. All the indications were 

 that these were migrants, and I concluded that they came from the 

 walnut trees, because there were no other infested trees near; in fact, 

 no trees of any kind nearer than the walnuts. This fact is interest- 

 ing, because the worms had to travel not less than 100 feet. 



Mr. W. B. Herms, who remained at the laboratory until August 31, 

 was kind enough to observe the worms for me after my departure, 

 and reported that they advanced only a little farther east into the 

 choke-cherry bushes and became fewer in numbers, evidently having 

 wandered off in search for a place to pupate. The trees began to 

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

 Riley, in his report, previously mentioned, states that many of the 

 trees even began to flower. 



A small hop-tree (Ptelea trifoliata) immediately under the webs in 

 the walnut trees was injured but little, the worms evidently having a 

 decided aversion to it. At one time a small web was spun in it, and 

 some worms were wandering about, but they all soon deserted it. 



In the early part of the forenoon I usually found some stragglers 

 upon the ground, evidently en route from the walnut trees, and which 

 had been overtaken by daylight. These were found 10 to 30 feet 

 from the walnuts and invariably headed away from these. The 

 majority traveled eastward to the cherry trees and westward to the 

 hackberry trees. Some, however, were wandering to all points of the 

 compass, the smaller number to the north and the south. To the 

 south was a plot of bare sand, and to the north also sand, but with 

 more grass and no trees. The routes to the east, west, northwest, and 

 southwest were more shaded. I should add, perhaps, that the soil 

 here, as everywhere at Cedar Point, is lake sand, and seldom more 

 than sparingly covered with wild grass. Upon none of the stragglers 

 observed did I discover a trailing thread of silk ; in fact, I found but 

 little silk anywhere along the lines of travel except to the east, where 

 the choke-cherry bushes were only a few feet from the walnut trees. 

 I found many dead worms along the line of travel, some plump and 

 fresh, others dried up. Many were found in little pits the size of an 

 ordinary heel. It occurred to me that these worms had died from the 

 heat, since all the lines of travel Avere exposed, more or less, to the 

 sun's rays during some part of the day. Again, the majority of the 

 dead worms were found to the south, where the sun was hottest. To 

 test my surmise that the dead worms upon the ground died from 

 excessive heat, I placed three in a small pit of the size mentioned. 

 They labored incessantly in an effort to get out, and all died within 

 ten to twenty minutes (one in ten, one in fifteen, and one in twenty). 



