16 FOURTH ANNUAL REPORT OF 



light, flat and broad broora, thus detaching the bugs which fall to the bottom 

 of the trap. Whenever the trap is filled the bugs are emptied out through 

 a sliding door b, and destroyed in whatever manner the operator sees fit. 

 A good size for this trap is 2 1-2 feet in height; 15 inches from flange to 

 flange and 7 inches across the narrow way of the pocket. It should be made 

 of tin or, if of wood, the pocket shQuld be lined with tin j as when kept smooth 

 or moistened with oil or water the bugs cannot easily crawl out, as one goes 

 from hill to hill. This contrivance is but an imj^rovement on the common 

 tin pan, and its principal merit lies in its simplicity and cheapness. 



The great difficulty with all mechanical contrivances of this kind, lies 

 in the fiict that they can only be used when the vines are of a considerable 

 size, whereas the enemy must be most persistently fought from the moment 

 the ground parts to give way to the sprouting tuber, until the plants are a 

 few inches high. Hence the great advantage of Paris green. 



A cheap, rapid and eifective method which commends itself to the good 

 sense of every one, is for one person to go along the rows with a short- 

 handled broom and by quick motions knock all the bugs o% while a second 

 person follows immediately after, dragging by a single horse a heavy bun- 

 dle of brush, or close-toothed harrow made for the purpose. Some of the 

 bugs will escape being killed, and a few of the younger larvae may not be 

 knocked off"; but the operation is so rajjidly performed that it will bear 

 repetition as often as necessary. 



Natural Enemies increasing. — To those who have carefully watched 

 the eastward progress of this insect, the manner in which its natural ene- 

 mies have increased in number and kind is interesting and significant. In 

 previous Eeports fourteen cannibal or parasitic insects, sj)ecially observed 

 to attack it in one state or another have been figured, and I am now able 

 to add seven more to the list. The toad, and perhaps some other reptiles 

 devour them, and among birds the crow has been observed to do so. 

 Among domesticated birds, the duck was for several years the only species 

 that would touch it, and chickens for a long time would invariably give it 

 the go-by. Last year I stated that chickens had learned to eat the eggs, and 

 had even acquired a taiste for the young larvae; but this year cases are 

 numerous, in various parts of the countr}^, where the beetles, as well as the 

 larvae and eggs have been devoured by them. I know of one case near St. 

 Louis where, with a few specimens of the common May Beetle, no less than 

 • thirty-one perfect specimens of the Colorado Beetles were found in the crop 

 of one chicken ; while in another instance, in the same neighborhood, the 

 chickens forsook every other kind of food for these nauseous insects. In 

 these instances the chickens have taken naturally to the new food, but it 

 has been shown (See Dr. Brown, Trans. Ind. Hort. Soc, 1871, p. 81) that 

 they may easily be taught to like it, by first shutting them up and, after 

 denying them all animal food for about ten days, turning them into an 

 infested potato field and keeping them there. Indeed, coops may be taken 

 into such a field, and young chickens raised there to good advantage. To 

 these birds we may also add that blithe and pretty field companion whose 



