AND OTHER INJURIOUS INSECTS OF I907 AND I908. IO9 



the bark of trees, fences, etc. In these secure retreats (where they 

 are at this date) each caterpillar changes to a brown pupa, which 

 emerges as a month in the spring, mating and egg-laying quickly fol- 

 lowing its emergence. Parasites undoubtedly play a part in the life 

 history of this pest, and this department plans to rear thein to deter- 

 mine their abundance and the species. 



No insect better illustrates the efficacy of "an ounce of pre- 

 vention" than the Fall Web Worm, and before this unpleasant and 

 dangerous feature becomes too conspicuous in our parks and boule- 

 vards, and in the beautiful private grounds in which the citizens of 

 Minnesota take so much pride, it is to be hoped that a little vigi- 

 lance and prompt action will be exercised when and wherever it makes 

 its appearance. 



THE POPLAR LEAF BEETLE, 

 Mclasoiiia scripta Fab. 



Fig. 51. The Poplar Leaf Beetle, enlarged and natural size. Original. 



Very destructive to nursery trees and windbreaks. In addition 

 to Poplar, it feeds also on Cottonwood and on Willows. The young 

 grubs feed for a time on the under surface of the leaves, later con- 

 suming the entire leaf. The pupa is found suspended from the leaves 

 during the summer. 



Remedies : Spraving zvitli arsenate of lead, having added enough 

 soap to the solution to make it spread evenly over the leaf. The 

 addition of soap is especially desirable ivlicn the smooth leaves of mil- 

 lozvs are sprayed, since the ordinary sprays are apt to roll off the 

 smooth surface. The under side of the leaf, as well as tJic upper, 

 should he hit by the spray, zvhere possible, in order to poison the very 

 young grubs feeding there. 



The colonies of grubs may also be knocked off the leaves by 

 jarring into a receptacle containing kerosene oil, or water and oil. 



