CHINCH-BUGS. 



165 



and the supply of water abundant; but we presume the Doctor- would 

 hardly recommend this plan as practicable on the forty thousand square 

 miles of territory overrun this year by Chinch-bugs, at the "West. 



All attempts to check the depredations of Chinch-bugs, by throwing 

 offensive substances upon them, such as tarred saw-dust, salt or lime, 

 have proved to be labor lost. The recommendation of the salt applica- 

 tion had the run of the newspapers the past season. Both this and the 

 air-slaked lime were thoroughly tried by Mr. Sells, of Bloomington, 

 without making any perceptible impression upon the bugs. 



DESTRUCTION OF CHINCH-BUGS BY NATURAL AGENCIES. 



This article would be incomplete without a brief reference to those 

 natural agencies by which this destructive insect is kept in check. Un- 

 like many of our noxious insects, such as the Plum-curculio and the 

 Codling moth, which are permanent fixtures, the Chinch-bug seems to 

 be subject to an irregular kind of periodicity, the causes of which are 

 not fully understood. "We have stated above that we have no reason 

 to expect any efficient aid in the extermination of Chinch -bugs from their 

 natural enemies. It is far otherwise with adverse climatic influences. 

 "We have already had occasion to refer to the important fact in the his- 

 tory of this insect, which has been established by repeated observation, 

 that cold rains, or a succession of heavy showers, especially in the month 

 of June, when the insects are small and immature, are fatal to them ; 

 and, therefore, that no fears of Chinch-bugs need be entertained for a 

 number of years succeeding a summer of this character. It is an un- 

 settled question whether there are any other adverse influences by 

 which the destruction of these insects, upon a large scale, is effected. 

 Are they ever destroyed by the severity of winter, as well as by the 

 rains of summer? 



In the observations made upon these insects, in their winter quarters, 

 by Dr. H. Shimer, in the winter and early spring of 1864-5, it appeared 

 that all the bugs which had been overtaken by winter in exposed situa- 

 tions, especially if above the snow line, were found to be dead. Even 

 of those which had found more secure retreats, under sticks of wood 

 lying upon the ground, and under the fallen leaves of apple trees, from 

 one-half to three-quarters were found to be dead in the spring. 



The observations of Mr. G. "W. Patten, above recorded, were of the 

 same character, but still more decisive. All the bugs found by him in 

 the month of December — although many of them were in tolerably well 

 protected situations, under the sheaths of corn-stalks which had been 



