18 THE CHINCH BUG. 
after the majority have become fully developed, and not as they reach 
the adult stage, as Professor Sajo has found to be the case with the 
European species, Blissus dorice. A migration by flight takes place in 
the fall, usually, I believe, during the period of Indian summer. The 
magnitude of such migrations depends in the spring on the number of 
individuals that have been in hibernation and in the summer and fall 
entirely on the abundance of the species during the current year. If 
there has been no great abundance during the spring the summer 
flight will not be likely to attract attention. During the invasion of 
1896 in Ohio an individual alighted on my hand while I was riding on 
a street car in the heart of the city of Columbus. A heavy storm of 
rain has much influence in scattering the bugs in midsummer, and just 
preceding a heavy rain I have noted the fully developed adults very 
abundant on Indian corn plants, while immediately after the storm 
there would be very few to be found. As these storms were not always 
accompanied by high winds, I am led to believe that it is the rainfall 
that scatters the insects. 
In timothy meadows where the original attack has begun along one 
side and gradually extended inward, the line of separation between 
the entirely dead grass and the uninjured is frequently not over a yard 
in width, and within this narrow, irregular strip we may have the dead 
and brown, the yellowing indicating more or less serious injury and 
the perfectly healthy green of unattacked plants. This many-colored 
border may change but little in the space of a week or ten days, except 
to advance very materially, leaving the grass completely dead or dried 
up, while the clover plants were uninjured. This indicates that the 
females, after leaving their places of hibernation, do not spread out 
over any large area, but to a certain degree maintain their gregarious 
habits. I can but believe that these habits have been shaped by some 
past environment in which the species has been placed for a long period 
of time, as, for illustration, the inhabiting of bunches or tufts of grass 
more or less isolated from each other. 
To what extent pairing takes place in these places of hibernation 
before the insects make their way to the cultivated crops is a matter 
of considerable uncertainty. From my own observations I am not 
inclined to believe that more than a very insignificant minority follow 
this course. 
OVIPOSITION. 
According to most writers the eggs are deposited either about or 
below the surface of the ground, among the roots of the grass or grain. 
It is more than likely that this varies with the conditions, as the eggs 
are not infrequently found above ground about the bases of the plants, 
and even upon the leaves, though I have never found them there, 
but have often found them under the sheath of grasses. It would 
seem, then, that the eggs require a cool, damp, but not a wet locality. 
