ENTOMOLOGY 361 



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the striped cucumber beetle. Such a frame can be made by sawing 

 a barrel hoop in two, tacking the two halves together at their centers 

 at right angles to each other, and covering with the netting. 



Barriers to prevent the migration of the chinch-bug from the 

 ripening small grains to the corn afford frequently the best means 

 of protecting the latter during a chinch-bug invasion. One of the 

 most successful of these is the tar barrier. This is made by smooth- 

 ing a strip of ground along the side of the corn field next to the small 

 grain by drawing a well weighted float or stone-boat up and down 

 until a smooth surface is obtained. Two narrow lines of coal tar are 

 then poured along this strip at such a distance apart that the float 

 may be readily drawn between them. The tar may best be poured 

 from a watering pot with a small spout, from which the rose has been 

 removed. Holes similar to post holes are then dug at frequent inter- 

 vals, close up to the outside of the line of tar toward the small grain. 

 The migrating chinch-bugs, reaching the first line of tar, will turn 

 aside and march parallel to it, tumbling into the holes. It will be 

 seen that there must not be the slightest interval between the edge of 

 the hole and the tar line, as in that case the bugs would crawl be- 

 tween them. As fast as the holes are filled the bugs may be de- 

 stroyed by throwing a little kerosene upon them, and then dug out 

 to give place to others. If the bugs are very numerous, they will at 

 places crowd over the first line of tar, forming bridges of their own 

 bodies so that free passage is made for those coming behind. Fre- 

 quent examination is therefore necessary and the repairing of any 

 such breaks. The bugs that get in between the two lines in this way 

 may be crushed by drawing the float along between the two lines. 



To prevent larvae and wingless adult insects from climbing the 

 trunks of trees various forms of barriers have been devised. A strip 

 of paper composed of several thicknesses and tied around the tree 

 with a piece of string near its upper edge or at its middle so that the 

 lower edge projects from the tree at all points, is sufficient in some 

 cases and is the simplest form when it will serve the purpose. Paint- 

 ing a band around the trunk with some sticky substance is also a 

 common method. Besides these simple means, there are a number 

 of patented -appliances on the market that serve the purpose excel- 

 lently where the expense is not sufficient to prevent their use. The 

 tree bands are used mostly to keep off the trees migratory larvoe and 

 to prevent the wingless females of the canker worm from ascending 

 the trees to lay their eggs. 



Trunk Washes. To prevent the deposition of the eggs of vari- 

 ous wood borers various repellant substances are applied to the trunks 

 of the trees. One of the best of these is made by mixing hydraulic 

 cement with skimmed milk until it is of as thick a consistency as can 

 be readily applied with a whitewash brush. The trunk of the tree is 

 thoroughly painted with this before the egg laying season of the in- 

 sect feared. One application will suffice for the season. This is most 

 extensively used for the peach borer, but can be applied for other 

 forms. 



