INFLUENCE OF TEMPERATURE ON CHINCH BUG. 37 
have more definite grounds upon which to base our studies of meteoro 
Logical influences. Thus applied, the terms - wel " and "dry " sea- 
sons would include within them the two breeding periods of the 
chinch bug, ;it least largely so, north of latitude 30 N. Bui the his- 
tory of this species has shown thai there may he an excess of rain fall 
during this critical period and that -till a sufficient number of insects 
may develop to work serious injury over considerable areas of coun- 
Pio.il.- Map showing distribution of chinch bug in Ohio in 1896. (Author's illustration.) 
try. This is due to two. and perhaps more, causes. In the first 
place, an unusually heavy rainfall at long intervals, while bringing 
up the total for a given period, may have hut little effect in reducing 
the number of chinch bugs, while a much less amount of precipitation 
coming at short intervals and in the midst of the hatching season 
would cause a far greater mortality among the young. And. in the 
second place, the precipitation may come at the beginning or even 
