On unusually warm days of winter or spring when tlie temperature 

 remains for several hours at 60° or 70° some of the beetles emerge, but 

 they return if the weather cools. At Olney, 111., during a four-year 

 period, there was nearly a month's difference in the dates when weevils 

 began to leave their winter shelter. In 1921, movement from hiberna- 

 tion began on March 15; in 1918, March 25; in 1914. April 8; and in 

 1920, March 23. No precise data were obtained in Ohio, but such infor- 

 mation as we have, indicates that in the main the beetles are from two to 

 three weeks later in leaving their winter quarters at Delaware, Ohio, 

 than in southern Illinois. 



The time of their appearance in spring is not always contemporane- 

 ous with the appearance of the leaves. During some seasons they come 

 out in considerable numbers before the foliage is developed and cluster 

 on the swelling buds as if waiting for the leaves to appear. On the 

 other hand, in some seasons the leaves are three-quarters of an inch 

 long before the beetles are abroad. If there are one or two days of 

 exceedingly warm weather before the foliage starts, the beetles a])pear 

 in advance of the leaves, whereas if the foliage is developed by normal 

 weather the leaves are from Y^ to -)4 '"ch long before the beetles leave 

 their winter quarters. The above observations apply particularly to or- 

 chards which are in sod. 



In leaving their winter shelter many of the beetles crawl up the 

 trunk of the tree, but most of them crawl to the tip of grass blades or 

 other objects and thence take flight to the branches above. Their flight 

 is erratic and fortunately they do not travel long distances on the wing, 

 and they seem unable to take flight if even a moderate breeze is blow- 

 ing. If the wind is fitful they cling to their swaying perches, not at- 

 tempting flight until a lull comes, whereupon great numbers will spring 

 into the air almost simultaneously. 



After emerging in spring the beetles begin to mate and to feed upon 

 the swelling buds or expanding leaves. When the foliage is a little fur- 

 ther developed egg-laying commences. For this the female seeks the 

 midvein or one of the laterals on the under side of the leaf, and after 

 making a suitable cavity with her snout, deposits therein a tiny egg, 

 closing the cavity afterwards with a bit of excrement. 



The eggs hatch in about a week and the newly emerged larva begins 

 feeding in the blind end of the tuimel in which it lies, and proceeds 

 thence to mine out the inner substance of the leaf. At first the mine is 

 threadlike, lengthening in the genera! direction of the edge of the leaf, 

 and gradually increasing in width. At the edge of the leaf the mine 

 takes on a somewhat blotchlike form and when completed is about two- 

 thirds the size of a dime. The mine is rather cons])icuous because the 

 leaf tissue on both its upper and lower sides dies and turns brown. 



On an average the larva becomes full grown in seventeen days, 

 whereupon it causes an expansion in a jiart of the ujjjier and lower 

 surfaces of the mine which takes the form of a blister a little less than 



