18 
ever, its own cocoon within the web. When the insect becomes 
abundant, cocoons mav be found under fences and at the edee 
of clapboards on houses, and in many similar places. 
One of the most disturbing peculiarities of a brown-tail in- 
festation is the fact that the long barbed hairs already mentioned 
are covered with a poisonous excretion, and that they readily pierce 
the skin, causing an irritating rash which occasionally results in 
serious illness. "Indeed," says Dr. Howard, "it is not necessary 
for the caterpillar itself to come in contact with the skin; at cer- 
tain times of the year it seems as though the hairs were actually 
floating about in the air. At the time of the caterpillar's change 
of skin, and particularly at the time of the spinning of the cocoon 
and the final change, certain of these hairs appear to become loos- 
ened in such a way that they are carried by the wind." Others 
report that these poisoned hairs may collect on clothing hanging on 
the line, to the intense annoyance of those who wear it. 
The readiest and most obvious means of controlling the brown- 
tail moth, and certainly the easiest one, is the collection and destruc- 
tion of the winter nests after the leaves have fallen. After April 
the only practical remedy is spraying the trees with an arsenical 
mixture. The young caterpillars are readily enough destroyed with 
arsenate of lead, but the older ones become resistant to poison 
sprays, and as much as five pounds of the arsenate to a barrel of 
water has been found necessary to kill the full-grown caterpillar. 
When this insect appears within our borders it will be most 
destructive in parks and towns and forest plantations, since these 
are not regularly sprayed and will require a special treatment to 
protect them. It will also aid the San Jose scale in putting out 
of business the neglectful or indifferent orchardist, but the business 
fruit grower, who values his property and takes care of it as well 
as he can, w^ill have much less to fear from this insect, since his 
ordinarv spraying operations will be practically certain to destroy 
it as it enters his orchard. The fact, however, that the full-grown 
caterpillar requires a heavier insecticide treatment than does the 
codling-moth and the canker-worm, for which most of our spray- 
ing is done, may make it necessary to go over the orchard in winter 
to remove and destroy the hibernating colonies. 
The gypsy moth may be more briefly considered, altho it 
is even a more destructive pest than the brown-tail, especially for 
the reason that it eats the leaves of evergreens — trees which are 
often killed by a single defoliation. It is conveyed to distances in 
the caterpillar stage only by accident. Passing wagons, automo- 
biles, trolley cars, or even railroad trains, may carry the cater- 
pillars to uninfested districts, but in this way its spread is slow. 
especially as all possible measures are being taken in infested dis- 
tricts of New England to keep the roadsides free from the pest. 
