222 NATURE STUDY AND LIFE 



the nurserymen. The young trees and all other stock, if 

 there is the least suspicion that the scale may be present, 

 are put in a tight box and treated with the fumes of 

 hydrocyanic acid, somewhat as we learned to kill insects 

 in the cyanide bottle ; so that, if such stock is accompanied 

 by a certificate that it has been so treated, we need have 

 no fear in* planting trees, even if there are a few dead 

 scales on them. 



The following insects are so well known and found 

 so easily that I shall do little more than mention their 

 names. On account of their importance they should be 

 included in a nature-study course. 



The Colorado Potato Beetle should be studied in the spring. 

 It is a good form to use in lower grades, in connection 

 with their garden work, to show feeding, eggs, and larvae. 

 Professor Fernald has made a careful estimate that this 

 insect collects a tax from the people of Massachusetts of 

 not less than ^75,000 a year. If every one in a neighbor- 

 hood would sprinkle his potato vines with a mixture of one 

 part of Paris green to twenty of flour or plaster, as required, 

 for the first week or two after they come up, there would 

 be no more potato beetles that season. They pass the 

 winter as adults in the ground, and since a female may lay 

 from 500 to 1000 eggs, and since there are from two to 

 four broods a season, this is the time to do thorough work. 



The Asparagus Beetle, Crioceris asparagi, has a life story 

 similar to that of the potato beetle. 



The Striped Cucumber Beetle, Diabrotica vittata. — The 

 eggs are laid about the roots of cucumber, squash, melon, 

 and other plants of the same family, and the larvae feed 

 upon the roots. 



