THE NANTUCKET PINE MOTH. 751 



shoot may be in auy part, even toward the tip, where it can push a lateral passajje 

 obliquely toward the base of one of the needles. Siicli a burrow, vertical in this case 

 and not obli(]ue, may be seen in fig. 8 on the right hand of the regular burrow at the 

 tip of the shoot. Several indeed may occupy differeut parts of the same shoot; the 

 place selected is slightly enlarged to form a longitudinal cell, at the upper or outer 

 eud 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 never 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 change 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 chosen well for 

 itself but ill for the tree. The very richness of the nourishment of which it robs the 

 tree tends to the immense abundance of the insect, which, attacking the tree at 

 every growing point, efiectually puts an eud 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 bos I have obtained three kinds of 

 hymenopterous parasites — one a species of Bracon proper, another a minute Peri- 

 lampus, 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 

 eflfectual 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 and 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^ burrow, and will infallibly die if the shoot is removed from 

 the tree; its sustenance will be gone and it can not crawl about sufficiently to tiud 



