28 THE CHINCH BUG. 
In the timothy meadows of northern and northeastern Ohio, how- 
ever, the principal injury is done during August and September, and 
in favorable weather on into October. Now, if we allow sixty days 
for development from the egg, it would be September before the ap- 
pearance of the adults of the brood to which these various young 
belonged. If all eggs were deposited immediately, it would be 
November before the adults of the second brood would begin to 
occur, a condition of affairs that has never been observed. <As pre- 
vously shown in this bulletin, the first brood is fully developed in 
northeastern Ohio by the first of September, but there certainly is 
no indication that a second brood of young is developed during Sep- 
tember and October. It would seem, then, that from northern Ohio 
through New York, New England, and probably to Nova Scotia 
the adults from the first brood of larve winter over, and that there is 
here but one annual brood. 
DESTRUCTIVENESS LARGELY DUE TO GREGARIOUS HABITS. 
Attention has been directed previously to the gregarious habits 
of the chinch bug, and we only refer to the phenomenon again be- 
‘ause it is to this that its destructiveness is largely due. It is not 
the excessive numbers, but the persistency with which they will 
congregate en masse on limited areas, that renders their attacks 
so fruitful of injury. With an ample supply of food the young 
develop and leisurely diffuse themselves over the adjacent fields, 
and there are neither swarming flights nor migrations. In 1884, 
in northern Indiana, a small field of wheat was severely attacked 
by chinch bugs. At harvest there was every prospect of a migration 
from the field of wheat to an adjacent one of corn, and the bugs were 
present in sufficient numbers to have worked serious injury to the 
latter: but the wheat had grown up thinly on the ground, and there 
had sprung up among the grain a great deal of meadow foxtail grass, 
Txophorus (Setaria) glaucus, and panic grass, Panicum crus-galli, 
and to these grasses the bugs transferred their attention, finishing 
their development thereon, and later, so far as could be determined, 
they scattered by flight out over the adjacent fields, working no fur- 
ther injury. Pedestrian migrations may continue for a fourth of a 
mile or even more, but on reaching a suitable food supply the tend- 
ency of the bugs is to congregate upon their food plants until these 
are literally covered with individuals: varying in color from the 
black and white of the adults to the bright vermilion of the more 
advanced larvae. (See fig. 5.) Whatever tendency there is ex- 
hibited toward a wider diffusion is confined to the adults, the others 
remaining and leaving in a body only when the plant on which 
they have congregated has been drained of its juices and has begun 
