1911] The Ottawa Naturalist. 67 



in the case of the two moths to which reference has already been 

 made, the gypsy moth and brown-tail moth, which have been 

 introduced into America. They did not bring with them their 

 parasites which keep them in check in European countries, and 

 in the absence of these natural means of control they have 

 increased enormously. For example, between the years 1896 

 and 1902, the brown-tail moth spread so rapidly that the infested 

 area increased from about 26 square miles to 1,500 square miles. 

 To-day, their parasites are being imported from Europe and 

 Japan, and liberated in the United States in the hope that 

 ultimately these natural means of control will render these 

 insects no longer a conspicuous pest. This is a single instance 

 out of many, showing the effects of this removal of the balance 

 which Nature normally maintains, but with which man is con- 

 stantly interfering. It can also be shown how insects affect 

 commerce, prevent the colonization of countries, how they 

 influence health, and how they may be responsible for the down- 

 fall of a people. No other group of animals bears so serious and 

 important a relation to man himself, and any instruction, there- 

 fore, on insect life in which consideration is net given to these 

 practical aspects of the question is as incomplete as a human 

 being without hands. 



In rural schools such knowledge is a sine qua non, and has 

 been imparted in a number of such schools with which I am 

 acquainted, but frequently owing to the want of the particular 

 knowledge on the part of the teachers themselves such instruc- 

 tion is not given. The absence of instruction and suitable text 

 books on the subject make this, to some extent, excusable, but 

 if goods are demanded there is usually some attempt made to 

 supply them, and if teachers will demand instruction of the 

 nature I have endeavored to describe, efforts are sure to be 

 made to provide the same. It is a question which rests with 

 teachers, and to those these random remarks are made in the 

 hope that a few may fall on good ground in addition to those 

 which are destined to fall and be choked by the thorns of an 

 over-crowded curriculum. 



CONCHOLOGICAL NOTES. 



Mr. Frank Collins Baker, of the Chicago Academy of Sciences, 

 has issued his monograph on the Lymnaeidae of North and Middle 

 America, recent and fossil. The volume is of 539 pages with 

 53 half-tone plates, and numerous illustrations in the text. 

 The morphology of Lymnaea is fully dealt with, and a new and, 

 I think, highly satisfactory classification arranged, based in the 



