154 SECOND REPORT OF THE STATE ENTOMOLOGIST. 



of mating, and again in the autumn, large numbers are frequently seen 

 upon the wing, and it is believed by Dr. Shimer and others, that at no 

 other time do they indulge in flight, except at these two nuptial seasons, 

 which, in Illinois, occur in May and August (see Proceedings of the 

 Academy of Natural Sciences of Philadelpliia, for May, 1867). This, 

 however, is certainly an error, for there is reliable evidence of their 

 migration upon the wing, for other reasons, apparently, than from want 

 of food. See the statement of immense swarms flying eastward, in 

 Iowa, on and about the 19th of June, in Prof. Forbes' 12th Report on 

 the Insects of Illinois, p. 34. 



From the gradual development of the eggs within the ovaries, and the 

 long-continued oviposition, it follows that the final maturity of the insect 

 is far from uniform. Hence it is that it is found in such different sizes 

 and stages at any time throughout the season. The ripening of spring 

 wheat may be given as about the time that the larger portion of the 

 brood has acquired wings. During the wheat harvest they are often 

 very abundant. 



The second hrood. — -In July, eggs are laid for a second brood, which, 

 according to observations made in Illinois, by Prof. Forbes, in 1882, 

 were hatched about the middle of the month. Matured individuals 

 were seen, the first, on August 8th; by the last of August, about one-half 

 of the brood had matured, and the entire brood had become winged 

 by the middle of September; by the 25th of September they had ap- 

 parently ceased feeding. On the 3d of October they were rare in the 

 corn-fields, and had evidently scattered in search of winter quarters. 



As a general rule, this brood is less injurious than the first, as the 

 corn and their other food-plants are more advanced and better able to 

 resist attack. 



Hibernation. — At the approach of cold weather they cease feeding, 

 desert their food-plants and seek sheltered places where they may pass 

 the winter. Some of them merely crawl down the stalks and stems and 

 enter the ground, burying themselves therein .to a moderate depth. 

 Others take wing in search of secure retreats in any rubbish that may 

 be found upon the borders or in the vicinity of the field, such as logs, 

 old fences of wood or stone, coarse weeds, heaps of straw, leaves, etc. 

 Stacks and piles of corn-stalks are particularly attractive to them, and 

 are often employed as a lure, to serve as a holocaust later in the season 

 for the myriads that have sought their shelter. Woodlands near the 

 fields where they have abounded, furnish harborage for large numbers 

 during the winter. 



In the torpid condition in which they hibernate, they are capable of 

 enduring an extreme degree of cold, and may even be frozen, it is said, 

 without suffering harm. 



