10 BULLETIN 899, U. S. DEPARTMENT OF AGRICULTURE. 
It might be added that in some cases men applying gipsy moth 
tree-banding material have received temporary injury to the face 
and hands, particularly the latter. In such cases the operator ex- 
perienced a burning followed by soreness similar to that of sun- 
burn, the skin later peeling off to some extent. Not more than 50 
per cent of the men using the material experienced any difficulty 
in this respect. It is possible that injury to those susceptible might 
be prevented by coating the skin with vaseline immediately before 
using the banding material. 
SIZES AND SHAPES OF BANDS USED. 
Experiments have been conducted in the field to determine what 
size, shape, and thickness of bands are most efficient (fig. 4). A gun, 
used in molding bands on the trees, was so arranged that nozzles of 
various sizes could be attached to it. Bands rectangular in shape, 
Fig. 4.— Showing some of the forms of hands of gipsy moth tree-handing material with 
which experiments were made. The rectangular form proved most successful. 
varying from J to 2J inches in width were tested, and some having a 
thickness of T V mcn a ^ top, \ inch at bottom, and ly\ inches broad; 
others T V inch at top and bottom and T % inch in middle, 1 inch wide ; 
also some $$ inch at top, Jfc inch near bottom, with rounded surface 
on lower edge, and a type having a thickness at top and bottom of J 
inch, sloping to a thin smear in the middle and 1 T 5 B - inches wide. 
The rectangular bands ^| inch broad and ^ inch thick proved 
both economical and efficient where the infestation of caterpillars was 
not too severe. Bands of this size have been used on a large scale 
in the extermination work against the gipsy moth in the border 
territory, and were found to be the most satisfactory under average 
conditions. Bands of these dimensions are very efficient when at- 
tended once or twice weekly during the active caterpillar season — 
the surface refreshened, the bridges removed, and the caterpillars 
beneath killed. The frequency with which the bands should be at- 
tended depends upon the degree of infestation, and too much stress 
