88 THE CANADIAN ENTOMOLOGIST. 



spread of the oyster-shell, San Jose and other kinds of scale insects, also 

 of many kinds of Aphides, some borers, and not a few of the other sorts 

 of orchard-infesting insects. 



Greenhouses must be held largely responsible for the spread of many 

 small pests, such as the red spider, mealy bug, and Aphides which attack 

 house plants especially. The greenhouse men get these insects on stock 

 received from different sources, and then, by retailing their plants to their 

 numerous patrons, they distribute these troublesome creatures to almost 

 every home in the country. As examples of how easy it is to introduce 

 such insects, and how difficult to get rid of them, may be mentioned the 

 introduction of the chrysanthemum black Aphides, and of the white fly at 

 the Agricultural College, Guelph. Up to three years ago there were no 

 chrysanthemum black Aphides here, but, about that time, Prof Hunt re- 

 ceived some cuttings from one of the United States greenhouses* He cx 

 amined the cuttings for insects, but so carefully had they concealed them- 

 selves, from some cause or other, that he saw none, and supposed the 

 plants free from anything of this sort. A couple of days afterwards, how- 

 ever, when he happened to look at the chrysanthemums he saw many of 

 the black Aphides on them, and, in spite of all his efforts to get rid of the 

 ])ests, he has hitherto failed to do so. In the case of the white fly, a man 

 living at some distance from Guelph, when on a visit to the college, 

 brought along some leaves of cucumbers to- find out what was injuring 

 them. When the Professor had partly opened the parcel, he observed a 

 few tiny insects fly out. He at once closed it tightly and sought to cap- 

 ture the ctdprits, but in vain. These few escaped individuals have been 

 the progenitors of the numerous white flies that infest many plants around 

 the college greenhouse. Such are merely two examples of many similar 

 ones that every floriculturist could give from his own experience. 



Another extensive means of distributing insects is by shipments of 

 fruit. In these times of cold storage and rapid transit, fruit can be con- 

 veyed across the continent in a very few days, and whatever insects are to 

 be found in it will have a good chance to arrive at their destination unin- 

 jured. Anyone who has ever packed apples knows how impossible it is 

 to prevent at least a few of those infested by codling moth larvte o'' other 

 insects being sent in each shipment. The fact is that there is always a 

 possibility of some individuals, of whatever species of insects infest the 

 orchard, getting into the fruit boxes or barrels and escaping uninjured 



