20 SECOND ANNUAL REPORT OF 



now (Dec. '69) a number of cocoons which were formed by a second 

 brood of larv£e. It is quite reasonable, therefore, to infer that the 

 Chinch Bug may produce even more than two broods in the more 

 Southern States. 



It is these two peculiarities in the habits of the Chinch Bug, 

 namely, first, its continuing to take food from the day of its birth to 

 the day of its death, and secondly, its being either two-brooded or 

 many-brooded, that renders it so destructive and so difficult to com- 

 bat. Such as survive the autumn, when the plants on the sap of 

 which they feed are mostly dried up so as to afford them little or no 

 nourishment, pass the winter in the usual torpid state, and always in 

 the perfect or winged form, under dead leaves, under sticks of wood, 

 under fiat stones, in moss, in bunches of old dead grass or weeds or 

 straw, and often in corn-stalks and corn-shucks. In the fall and win- 

 ter of 1868, 1 repeatedly received corn-stalks that were crowded with 

 them, and it was difficult to find a stalk in any field that did not re- 

 veal some of them, upon stripping off the leaves. I have even found 

 them wintering in the gall made by the Solidago Gall-moth (GelecJiia 

 gallcesolidaginis), described in the First Report. 



In the winter all kinds of insect-devouring animals, such as birds, 

 shrew-mice, etc., are hard put to it for food, and have to search every 

 hole and corner for their appropriate prey. But no matter how 

 closely they may thin out the Chinch Bugs, or how generally these 

 insects may have been starved out by the autumnal droughts, there 

 will always be a few left for seed next year. Suppose that there are 

 only 2,000 Chinch Bugs remaining in the spring in a certain field, and 

 that each female of the 2,000, as vegetation starts, raises a family of 

 only 200, which is a low calculation. Then — allowing the sexes to be 

 equal in number, whereas in reality the females are always far more 

 numerous than the males — the first or spring brood will consist of 

 200,000, of which number 100,000 will be females. Here, if the species 

 were single-brooded, the process would stop for the current year; 

 and 200,000 Chinch Bugs in one field would be thought nothing of by 

 the Western farmer. But the species is not single-brooded and the 

 process does not stop here. Each successive brood increases in num- 

 bers in Geometrical Progression, unless there be something to check 

 their increase ; until the second brood amounts to twenty millions, 

 and the third brood to two thousand millions. We may form some 

 idea of the meaning of two thousand millions of Chinch Bugs, when 

 it is stated that that number of them, placed in a straight line head 

 and tail together, would just about reach from the surface of the earth 

 to its central point — a distance of four thousand miles. 



According to the reasoning of Dr. Henry Shimer, of Mr. Carroll, 

 Illinois, who published an interesting paper on this insect in the pro- 

 ceedings of the Academy of Natural Science of Philadelphia for May, 

 1867, the Chinch Bug takes wing only at its love seasons, which occur 

 in his locality in May and in August. His views on this subject are 



