INSECTS. 



171 



od of mild, open weather, in winter. Those which rise 

 in autumn or in winter are less numerous than those which 

 ascend in spring ; but, being very prolific, they do much 

 injury. One method of preventing the ravages of the 

 worm is to bar the ascent of the females up the stem of 

 the tree. This has generally been attempted by tarring j 

 of which there are several modifications : — 



1. A strip of linen or canvass is put round the body of 

 the tree, before the females begin their ascent, and well 

 smeared with tar. The insects, in attempting to pass this 

 barrier, stick fast, and perish. But this process, to com- 

 plete the desired effect, must be commenced about the first 

 of November, and the tarring continued, when the weather 

 is mild enough to permit the worms to emerge from the 

 ground, till the latter end of May, or till the time of their 

 ascent is past. - It is necessary to fill the crevices in the 

 bark with clay mortar, before the strip of linen or canvass 

 is put on, that the insects may not pass under it. Having 

 put on the strip, which should be at least three inches wide, 

 draw it close, fasten the ends together strongly, then tie a 

 thumb-rope of tow round the tree, close to the lower edge 

 of the strip. The design of this is to prevent the tar from 

 running down the bark of the tree, which would injure it. 

 It should be renewed, in moderate weather, once a day, 

 without fail. The best time is soon after sunset, because 

 the insects are wont to pass up in the evening, and the tar 

 will not harden so much in the night as the day. 



2. Another mode of tarring is to take two pretty wide 

 pieces of board ; plane them ; make semi-circular notches in 

 each, fitting them to the stem or body of the tree ; and fasten 

 them together securely at the ends, so that the most violent 

 storms may not displace them. The crevices betwixt the 

 boards and the tree may be easily stopped with rags or 

 tow ; then smear the under-sides of the boards with tar. 

 The tar, being defended from the direct rays of the sun, 

 will hold its tenacity the longer, and, therefore, need not 

 be frequently renewed. The trees, in this way, will be 

 less liable to be injured by the drippings of tar, by leaving 

 a margin of two or three inches, on those parts of the 

 boards which are next to the trees, to which no tar is ap- 

 plied. 



3. Another mode of blockading the paths of the insects, 

 in their ascent up the trees, is to enclose them with collars, 

 or circular slips of tin. Of this method we have seen some 

 notices, but no description. We presume, however, that 



