THE PINE-I<EAF AND THB GREEN-WINGED CHERMES. 2O3 



The full grown Chermes acquire wings about the middle of 

 June when they leave the spruce galls and seek the white pine. 



Remedial Measures. There would seem to be no practical 

 method of combatting this insect in forest growth. With orna- 

 mental trees, however, the galls could be removed from the 

 spruce previous to the emerging of the winged form. 

 Also if the species proves constantly troublesome it might be 

 desirable not to plant the white pine in the vicinity of black 

 or red spruce and vice versa. 



Spraying with whale-oil soap ( i pound to 2 gallons of water) 

 would doubtless destroy the young on the' white pine shoots, 

 but it is doubtful that this would be usually worth while in 

 Maine where Syrphus flies abound. The larvae of these, little 

 light colored maggots, have been found to feed industriously 

 on the young Chermes. So numerous are these beneficial mag- 

 gots at times in the midst of the white waxy secretion of the 

 Chermes that they are sometimes mistaken by people submitting 

 them for determination as the cause of the trouble. 



The Green-Winged Chermes (Chermes abietis Linn). 



An entirely different sort of gall common in Maine on the 

 White Spruce, and Norway Spruce, is caused by another 

 species of Chermes which is here termed the "Green-winged 

 Chermes" as the conspicuous and constant green tinge of the 

 wings is a character which will readily serve to distinguish it 

 from the "Pine-leaf Chermes" by those who would find a more 

 technical comparison troublesome. 



Fig. 45 shows 3 of these galls together with 6 cones, about 

 natural size on a white spruce twig. It will be seen that these 

 galls differ from those shown in Fig. 44 in not being cone-like 

 and in not being characteristically terminal on the shoot. These 

 abietis galls do not usually cause the death of the shoot on which 

 they grow but they do cause deformed branches and frequently 

 ruin a small tree for ornamental purposes. Such galls are very 

 abundant on the Norway spruces on the University of Maine 

 Campus. That they are troublesome on native spruce in this 

 locality is shown by the fact that on a single white spruce 3 

 feet tall more than 990 of this season's galls were -counted 

 August I, 1909. Where so numerous, these galls are much 

 smaller than those shown in Fig. 45. 



