OF THE STATE ENTOMOLOGIST. 



25 



that the parent Hessian-fly {CeGidornyia destructor) makes its first 

 appearance in this latitude the fore part of September, and usually 

 leaves by the end of the same month, we may avoid its injuries by 

 deferring the planting of our grain till October. And if the parent 

 Army-worm {Leucania unijjuncta) deposits her eggs at the base of 

 grass stalks in the fall of the year, we may avoid the ravages of her 

 progeny by burning the stubble in the winter. A great many species 

 which, like the Army-worm, are difficult to control in their other 

 stages, are thus readily killed in the egg stage. 



Cuke. — The second method, namely, the cure of the evil when 

 once it is upon us, is sometimes sufficientlj' easy ; at others, almost, or 

 quite, impossible. As already stated, we have here two distinct lines 

 of action. That of killing the pests requires our ingenuity in the 

 construction of mechanical devices, or our time and patience in the 

 test and repeated trial of some external application that will kill the 

 enemy, while it leaves the plant, or the animal, uninjured. 



[Fig. 10.] 



Here we learn the value of such contrivances as Dr. Hull's Cur- 

 culio-catcher, (Fig. 10*), and the many modifications of it that have 



* This is a modification of Dr. Hull's wheeling machine, (3d Kep. Fig. 2) , which raodiflcation he 

 U5ed with good effect last summer, and which I described in the Scientific American, August 3, 

 1872, iu the following terms : 



' 'Dr. Hull was wont to claim that he could use his machine without injury to the trees, but the 

 present modification of it is an evidence that experience has taught hira differently. In all rolling 

 machines, whether upon one or two wheels, when the bumping was not done by the machine itself, it 

 had to be done by along pole, tipped with ruliber and used by a second person. But where I have 

 used such a pole and sei>arately jarred the larger boughs, the trees have been much injured in the course 

 of a single year's work, and i\i some instances killed outright. 



' ' The advantages of the present modification over the others may be thus briefly stated : It costs 

 less, and enables the operator to get close to the tree, to which he can give a sudden jar with a hatchet 

 or hammer. This is best done l)y striking a screw or spike previously inserted into the trunk, and 

 purposely made with a shoulder so as to prevent driving; or by striking the end of a limb previously 

 sawn squarely off. Such a hard, sudden jar, with an iron instrument, is far more effectual in bringing 

 down the beetles than the more sulidued bumping of a rubber m diet, as it is the sharpness and sud- 

 denness rather than the force of the blow which disturbs and alarms the little shy and cunning cus- 

 tomers we have to deal with. 



"The working of the machine is very well indicated in the illustration (Fig. 10). Therein a 

 bag, d, in the center, into which the operator can brush all fiiUen fruit, and a bottle of cheap alcohol 

 may be kept in the vest pocket, into which the beetles should be thrown; or they may be simply crushed 

 between the thumb and finger." 



