In the many accounts of this insect, I do not recall that attention has been called to the odour that is associated with insect, and which, in cases of excessive abundance, can be detected at a considerable distance away. Where the air is quiet it is often possible to detect the presence of a badly infested tree a yard away, and I presume that with more acute olfactories, such as insects are supposed by many to possess, even the presence of a more limited number of the scale might be detected at a much greater distance.