THE i:i;o\\ N-TAIL MOTH. 14 1 
spread. Like those of the gipsy mot h. the young cater- 
pillars have the habit of dropping down from the trees by 
spinning a strand of silk by which they are suspended, so 
that they may be picked up by any passing vehicle or may 
crawl upon it and thus be carried. Undoubtedly this often 
occurs, but as the spread takes place so much more rapidly 
by the flight of the moths, it is of minor importance. 
FOOD PLANTS AND INJURY. 
The [>e;ir is the preferred food plant of the caterpillars 
and is usually first infested where available; the apple 
comes next and, owing to its abundance, is the tree upon 
which the webs are first most commonly found in a newly 
infested section. All of the fruit trees and of the shade 
trees, elm, oak and maple, are freely attacked, in fact, 
almost all fruit, shade and forest trees, except the pines, 
spruces and other conifers are attacked in a badly infested 
district. Injury to woodlands and forests does not seem 
to be as serious as that inflicted by the gipsy moth, though 
often the defoliation is sufficient to cause large tracts to 
appear brown and seared. As yet, woodlands have not 
been infested sufficiently for a time long enough to defi- 
nitely determine just how serious the constant total or par- 
tial defoliation by the brown-tail caterpillars will be. It is 
well known, however, that any deciduous tree wholly de- 
foliated for three or four years is usually killed, and that 
the wood growth is seriously checked by partial defoliation, 
so that there is a distinct loss in the timber value. 
As the pest concentrates in towns, the shade and fruit 
trees suffer most and, unless the winter webs are removed, 
being defoliated year after year, become weakened and soon 
die. As when defoliated by cankerworms, tent-caterpillars 
or other caterpillars, fruit trees stripped of their foliage 
can hardly yield a crop of fruit and the control of the pest 
upon them is therefore imperative. 
DANGER TO HEALTH. 
One of the most serious effects of the presence of the 
brown-tail moth in a community is that of the peculiar 
skin disease it may produce. Some of the hairs of the full- 
grown caterpillars are furnished with minute barbs. When 
the caterpillars molt these barbed hairs are shed with the 
skin and as the skins become dry and are blown about by 
