8G THE CANADIAN ENTOMOLOGIST. 



orchards where the fruit was packed. In trunks, clothing, etc., were 

 brought house-infesting insects. In fact, whatever insect attacked any 

 particular kind of commodity was almost certain, sooner or later, to be 

 transported with that commodity. We should also remember that shijxs 

 anchored in a harbour during the time of unloading and loading their cargo 

 fi)rm a natural alighting place for the numerous insects that fly around m 

 the air. especially in the warm days and nights of spring and early sum- 

 mer, when the mating season for many is at its height. It is natural to 

 suppose, therefore, that not a few such insects would conceal themselves 

 on board and be carried abroad. 



Having thus shown how commerce can convey insects across the 

 ocean, from land to land, let us next consider how we are to account for 

 their wide and rapid spread in any country to which they may chance to 

 have been brought and to have gained a foothold. 



We shall first mention some ways in which this is done, independ- 

 ently of man's agency. The first way that would naturally suggest itself 

 is by means of their own powers of locomotion ; that is, by flying or 

 crawling from place to place. But in the case of scale insects, which only 

 move about for a day or two in all, and in that lime can only traverse a 

 fev/ feet, their spread would be very slow indeed, if they had to trust 

 solely to their own legs to convey them from, place to place. Observa- 

 tions have been made, however, which prove that they attach themselves 

 to the bodies of other insects, such as beetles and black ants, and also to 

 the feet and legs of birds, and by these are carried from one tree to 

 another. This would seem the natural explanation of finding, as some of 

 us have, oyster-shell scale on such trees as the red osier dogwood half a 

 mile away from any other infested tree. 



A third method of distribution is by means of winds and storms. 

 Gentle and constant winds -are of great assistance to insects in enabling 

 them to scent their food at long distances, and, in corroboration of this, it 

 has been observed that they come to their food, in most cases, against the 

 wind. Likewise, a light breeze aids the male insect, by his wondeiful 

 sense of smell, to find the female, and thus render the increase of the 

 species more certain. On the other hand, strong wii.ds have often been 

 known to convey such insects as butterflies and moths long distances. 

 Examples of this are the encountering by ships of swarms of buttei flics 

 fiir out at sea, whither they had been driven by the violence 'of the wind. 



