THE NANTUCKET PINE MOTH. 751 
shoot may be in any part, even toward the tip, where it can push a lateral passage 
obliquely toward the base of one of the needles. Sucli a burrow, vertical in this case 
and not oblique, may be seen in fig. 8 on the right hand of the regular burrow at the 
tip of the shoot. Several indeed may occupy different parts of the same shoot; the 
place selected is slightly enlarged to form a longitudinal cell, at the upper or outer 
end of which a passage is eaten into the open air, which may generally be seen with- 
out difficulty from the outside, if looked for near the base of the needles while the 
nest is uninjured. The holes left by the fallen needles must not be taken for these 
outlets; these uev^r seem to be taken advantage of, for from them usually exudes 
more or less pitch, closing the opening. To find on emergence from chrysalis that 
the means of egress of the moth was gone would prove disastrous to its life. Half 
through the eaten opening the chrysalis forces its way when about to chauge to the 
imago. 
It appears then that this insect, by selecting for its food in the larval state 
the point where the greatest amount of nourishment exists, has choseu well for 
itself but ill for the tree. The very richness of the nourishment of whicb it robs the 
tree teuds to the immense abundance of the insect, which, attacking the tree at 
every growing point, effectually puts an end to its life. The nearly dead tree I cut 
down was not more than 7£ centimeters in diameter and perhaps 4 meters high ; all 
but the very topmost boughs were dead, and here the foliage was extremely scanty, 
yet I could certainly have obtained forty or fifty caterpillars and chrysalids from this 
one tree. 
At first sight, certainly, there seems nothing to prevent this insect from con- 
tinuing its ravages and destroying every pine on the island. The only encourage- 
ment in this view is that then for want of pines the moth must die. In the hope of 
finding some natural means of its destruction, I have sought for parasites which 
might at least keep it in check. One such I found the first day, feeding upon a larva ; 
and by inclosing many infested twigs in a tight box I have obtained three kinds of 
hymenopterous parasites — one a species of Bracon proper, another a minute Peri- 
lainpus, both apparently undescribed. The latter is far the more abundant, but 
neither appears to be sufficiently common for us to place much reliance upon them, 
although they unquestionably serve to a certain extent to reduce the numbers of the 
moth. The only possible method of combating this evil is directly to destroy the 
Retinia in some one of its stages. Bonfires every day at dusk in the vicinity of the 
woods during the last week in April and the first week in May would doubtless 
destroy great numbers of moth laden with eggs, and would give healthy employ- 
ment and no small delight to the small boys of the island. But apparently the only 
effectual means of destruction is one indicated by the history of the insect, but which 
would be useless on the main land or without concerted action on the part of the 
inhabitants of the island. As already stated, the affected are speedily distinguished 
from the uninjured shoots soon after the caterpillar has commenced its work, by the 
presence of dead needles at the apex of an otherwise green shoot ; the presence of 
the enemy is thus infallibly disclosed. The month of June then is the time for 
operation aud the work to be done can be done once for all by breaking or cutting 
from every pine tree on the island every affected shoot. 
To be of any radical use this must be done during a single year, to leave none for 
propagation ; for the same reason it must be done to every tree, great or small, from 
the topmost boughs of the tallest trees to seedlings just springing from the ground; 
every scattered tree or seedling upon the island must be searched. I examined one 
isolated tree, about a meter high, growing a kilometer or thereabouts from the woods 
on the south shore, and it was thoroughly infested. To leave such a tree would be 
to have the labor and expense of the proposed assault in vain. The work must be 
completed within the month of June, since it is at this time that the caterpillar is 
only partly grown in it 3 burrow, and will infallibly die if the shoot is removed from 
the tree; its sustenance will be gone aud it can not crawl about sufficiently to find 
