﻿BARRIER -FACTORS IN GIPSY MOTH TREE-BAN 1)1 NO MATERIAL. 7 



above. Very soon after it swung on a third time, but after touching the band 

 with its mouth parts several times in quick succession, as before, it swung 

 down again and came to rest about 11 inches below the band. It remained 

 thus for four minutes, when, following application of the brush to the anal 

 end, it turned round and crawled down the stake. 



Placed a third time, the caterpillar paused and turned out of a straight 

 course about one-fourth inch below the band and on reaching it swung upon it 

 with the first pair of legs. It turned downward on swinging off and came 5 to 

 rest with its head about 2 inches below the band. It fell off tin; stake a few 

 minutes later when its anal end was touched with the brush. 



Placed once more, the caterpillar came to rest about two-thirds inch below 

 the band. On being touched with the brush, about two minutes later, it moved 

 up to within one-half inch and became motionless again, remaining thus for 

 several minutes, except for swinging its head three times. It became active 

 again on being touched once more with the brush, and on reaching the band it 

 swung on with the first pair of legs. After swinging off and crawling some- 

 what, it swung on and off a second time. It swung on and off a third time soon 

 after, and immediately afterwards swung on a fourth time, and continuing 

 upward worked its way up, by degrees, and across — 4.10 p. m. It took it a 

 minute to cross. 



In both instances, in which the band was crossed, the crossing was accom- 

 plished by a pawing-Iike motion of the legs and constant motion of the mouth 

 parts, and by the continual application of the latter to the band. 



"Well defined as were the results of this series of tests, of which 

 the above are examples, they were nevertheless not altogether satis- 

 fying. The fact is that the solid odorous bands, though strongly 

 charged with odor, were not — and could not be made— as strong in 

 this respect as the gipsy moth tree-banding material bands, owing 

 to the limited capacity of the flour to absorb and to hold the liquid 

 banding material ingredients. The results were indicative, indeed, 

 but hardly conclusive. 



SERIES II. 



To obtain more conclusive results, another series of tests was in- 

 itiated in which the odor condition was like or more nearly like that 

 in the gipsy moth tree-banding material. Actual gipsy moth tree- 

 banding material bands -were used here, the bands being bridged 

 (covered) with strips of riiedium-meshed cheesecloth (29 by 34 

 threads per square inch) of various widths. This combination ful- 

 filled the conditions in an excellent manner; the soft, or viscid, 

 quality of the material was eliminated and the odor apparently was 

 not to any great extent interfered with. This was particularly 

 t^ue in the case of narrow bridges. As in the first series, horizontal 

 bands on white paper, as well as ring bands around peeled vertical 

 stakes, were used. Bands made of ordinary white flour and water 

 (flour paste), of flour and molasses, of molasses alone, and of a com- 

 mercial sticky tree-banding material were used as checks, and they 

 served very satisfactorily. The ingredients of the gipsy moth tree- 

 banding material could not be used in the making of an odorless 

 band. 



The following typical illustrations, Experiments A, B, and C, 

 show the behavior of the caterpillars in this series : 



Experiment A. 



(Day bright, fairly warm.) 



ELEMENTS. 



1. Caterpillar. 



Fourth stage; good size for stage, pretty well advanced, pretty well fed, 

 active. 



