276 



Appendix. 



been repeatedly introduced since on trees brouglit from nurseries in other 

 states. It is now Isnown to be present in tlie following New Hampshire citiea 

 and towns, and probably is found in several others : Dover, Durham, Epping, 

 Intervale, Manchester, Rollinsford, Seabrook. 



The presence of the pernicious scale is difficult to detect until it becomes 

 sufficiently abundant to injure or kill the infested tree. It then appears as a 

 curious scaly crust on the bark. When only a few are present it is difficult to 

 find them, as they are simply small round spots of much the same color as the 

 bark, to be seen plainly only through a magnifying glass. Their presence gen- 

 erally is not discovered for two or three seasons after they first appear, by 

 which time they have usually spread to surrounding trees. 



ez. 



Fig. 2— Appearance of scale on bark: n, infested twig, natural 

 size; b, bark as it appears under band lens showing .scales in 

 various stages of development and young larvse. (Original). 



The individual scale is a small round object closely attached to the bark, 

 not more than one-eighth of an inch in diameter and having a darker raised 

 point near the center. At first these round scales are likely to be scattered 

 here and there over the bark, but as they increase in numbers they are nearer 

 together, touching or overlapping one another, and perhaps finally making a 

 thick, scurfy layer of a grayish color that obscures the natural color of the 

 bark, and is easily rubbed off with the finger. The presence of such a layer indi- 

 cates that the sap from the bark is being sucked out by millions of the insects 

 and that the health of the tree is being seriously impaired. 



