28 THE CHINCH BUG. 
In the timothy meadow- of northern and northeastern Ohio, how- 
. \<t. the principal injury is done during August and September, and 1 
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 adult- of the brood to which these various young 
belonged. II' all eggs were deposited immediately, it would he 
November before the adult- of the second brood would begin to 
occur, a condition of a Hair- that ha- never been observed. As pre- 
vously -low 11 in this bulletin, the fir-t brood is fully developed in 
northeastern Ohio by the first Of September, hut there certainly is 
no indication that a second brood of young is developed during Sep- 
ieinher and October. It would seem, then, that from northern Ohio 
through New York. New England, and probably to Nova Scotia 
the adult- from the first brood of Larvae 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 Ave only refer to the phenomenon again be- 
cause it i- to this that it- destrnctiveness is largely due. It i> not 
the excessive number-, but the persistency with which they will 
congregate en masse on limited areas, that renders their attacks 
-o 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 nights 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 bug- were 
present in sufficient numbers to have worked serious injury to the 
latter: but the Avheat had grown tip thinly on the ground, and there 
had sprung up among the grain a great deal of meadow foxtail grass, 
Ixophorus (Setaria) glaucus, and panic grass, Panicum crus-galli, 
and to these grasses the bug- transferred their attention, finishing 
their development thereon, and later, so far a- 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 i> t<» congregate upon their food plant- 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 larvse. (See fig. 5.) Whatever tendency there i- ex- 
hibited toward a wider diffusion is confined to the adult-, the others 
remaining and leaving in a body only when the plant on which 
they have congregated ha- been drained of it- juice- and ha- begun 
