146 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



REMEDIES. 



It is obvious that in swamps in the remoter parts of the country these 

 worms cannot be subdued ; they will run their course, and probably 

 such a visitation as that of 1881-'S2 will not happen again for a term of 

 years. To prevent their killing shade trees, particularly small ones, 

 jarring the trees will prove a good remedy, the worms once shaken off 

 the tree cannot ascend the trunk, as they do not, like canker worms, 

 climb trees or let themselves down by a thread. Small trees may also 

 beshowered with solutions of Paris green, or the various fluid insecticides 

 recommended in the recent reports of the Entomologist of the Depart- 

 ment of Agriculture. 



PARASITES. 



A number of cocoons sent us in 1882 by Mr. Atkins were found to be 

 in every case tenanted by a minute chalcid parasite, belonging to the 

 genus Pteromalus. If new it may be called Pteromalus nematicida 

 (Plate XII, Fig. 8). About a hundred of these issued from the cocoons 

 in the breeding-box during May, 1883. This parasite must therefore be 

 a most destructive enemy of the larch worm. 



We also noticed several bugs, a species of Podisus, near the common 

 spinosus, preying upon the fully-grown worms ; it ascends the trees and 

 pierces the worm with its beak, carrying it down the tree and sucking 

 its blood, rendering it lifeless. 



THE SPRUCE-BUD TOETEIX. 



(Tortrix fumiferana Clemens.) 

 Order LEPIDOPTERA; family TORTRICIDJE. 

 [Plate III, Fig. 3.] 



The most destructive enemy of the spruce and fir in Lincoln, Sagad- 

 ahoc, and Cumberland Counties, Maine, is the Spruce Tortrix. 



The habits of this insect while in confinement have been studied by 

 Prof. C. H. Fernald, of the Maine State Agricultural College, 'Orono, 

 Me., and his account published in the American Naturalist for January, 

 1881. In the account of the ravages of a caterpillar on the spruces 

 on the coast of Maine in Bulletin 7 of the United States Entomolo- 

 gical Commission, we refer to this insect, which we were unable to iden- 

 tify, as, after repeated search in the latter part of the summer, we failed 

 to discover any traces of the insect in any stages. In our account we 

 gave greater prominence to the operations of borers and bark beetles 

 than to those of this caterpillar; and while considerable damage was 

 undoubtedly done to spruces and firs in Sagadahoc and Cumberland 

 Counties by those beetles, from farther inquiries and field-work carried 

 on in June and July, 1883, in different parts of Maine, we now have 

 little doubt but that the destruction of spruces and firs along the coast 

 of the State was mainly due to the attacks of this insect. 



The different climatic causes alleged to destroy forest trees in general, 

 would, in the present case, have injured pines and hard- wood trees, as 

 well as spruces and firs, and the destruction would have been general ; 

 whereas the trees have been killed by a caterpillar which is not known 

 to live upon pines nor any trees but spruce, fir, and occasionally the i 

 hemlock and larch. Individual trees, or clumps of trees, were attacked, 



