21 



sons it may be both an insecticide and a fungicide. This prepara- 

 tion is made as follows : Six pounds sulphate of copper dissolved 

 in six gallons of hot water, four pounds of unslaked lime are slaked 

 in six gallons of cold water. After the lime is slaked and cool, 

 pour the two solutions together and add ten gallons of water. This 

 proves very useful in preventing rot and other troubles due to 

 fungi, and by adding to the mixture Paris green or London purple, 

 it becomes an insecticide as well. 



Besides the methods already mentioned numerous more or less 

 successful experiments are being made in difierent parts of the 

 country to ascertain the value of various tungi as insecticides. It 

 has been known for a long time that many insects were more or 

 less liable to be attacked by fungi and that they were destroyetl by 

 their growth, but it is only recently that any attempt has been made 

 to use this fact and to cultivate the fungi in order that they might 

 be used as insecticides. This has been done thus far only to a 

 limited extent, but it is not impossible that much more may be 

 accomplished in this direction. The spores of fungi are very 

 small, and can be kept for a long time without injury, and when 

 once their growth is started they develop with great rapidity and 

 spread with equal facility from one insect to another, destroying 

 quickly those infested, so that it is possible that a serious outbreak 

 of injurious insects be very ef^bctually and promptly checked by 

 means of fungi. 



It has seemed to the writer better to devote the remainder of 

 this paper to a definite group of insects rather than to study various 

 unrelated groups. Hence we will now turn our attention to 



IV. INSECTS INJURIOUS TO THE AMERICAN ELM. 



It will soon be <liscovered that however limited may be the field 

 of inquiry which the student of injurious insects may adopt, his in- 

 vestigations will necessarily carry him very far beyond the bounds 

 which his sui)ject may at first seem to draw tor him. In study- 

 ing those species of insects which attack the elm, we shall be 

 forced, and very readily, to discuss some of the worst pests which 

 infest fruit trees and other forms of vegetation, so that before we 

 have completed our task we shall find that the fruit grower and 

 the farmer may find that which is of value as well as the lover 



