BARRIER FACTORS IX GIPSY MOTH TREE-BAXDING MATERIAL. I 
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 1£ 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 to 
rest with its' head about 2 inches below the band. It fell off the 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 pa wing-like 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 IT. 
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 medium-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 w T as eliminated and the odor apparently was 
not to any great extent interfered with. This was particularly 
true 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, w^ere 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 s ; ze for stage, pretty well advanced, pretty well fed, 
active. 
