STUDIES ON THE CHINCH BUG* II, 



(Blissus leiicopterus, Say.) 



The economic entomology of this State has been distinguished, 

 during the last four years, by the longest period of continuous 

 chinch bug devastation known in the history of that insect; but as 

 evidences of the disappearance of this outbreak are now (Septem- 

 ber 30) beginning to accumulate, it is perhaps not too soon to write 

 its history. 



Its beginnings were apparent in 1885, when noticeable injuries 

 to com w'ere reported from ten counties of Southern Illinois.t In 

 1886, thirty counties of that region were seriously damaged, Wash- 

 ington county (about the center of destruction) being perhaps 

 worst infested. In 1887 the loss was severe in thirty-eight 

 counties of the southern district, and very noticeable in thirty- 

 seven others of Northern and Western Illinois J; while in 1888 

 small grain and corn were heavily infested throughout all the 

 southern counties, favorable weather alone enabling the crops to 

 withstand the injury better than the year preceding. The attack 

 was now considerably diminished in the center of the affected area, 

 but farther to the east, in Clay, Richland, and Crawford counties, 

 it was much heavier in the beginning of the season tlian the pre- 

 ceding year, its force decreasing, however, with the disappearance 

 of the first generation. On the extreme southern borders of the 

 State, on the other hand, it continued with undiminished severity, 

 the damage done in 1888 being greater than that in 1887, — greater 

 in Pope and Pulaski counties, I w^as informed, than ever before 

 since their settlement. There was thus apparent a wave-like prop- 

 agation outward from the center above mentioned, the crest of 

 the w^ave of increase requiring two years to pass from AVashing- 

 ton county to the Ohio Kiver. A similar grndual increase north- 

 w^ard was demonstrated by a comparison of the numbers of chinch 

 bugs in early spring of 1887 with those of the summer and fall, 

 in the counties of Montgomery, Christian, and Shelby. 



*ForArtide I, of this series, see 12th Report of the State Entomologist of niinoJ8,1882, pp. 32-63. 



tSee "Miscellaneous Essays on Economic EntomoloK.y" in Appendix to Transactions Depart- 

 ment of Agriculture, lUinoiH.'lHgD, ("vol. 23), p. 2:3. 



J.See table of injuries by counties on pp. 5 and 0. The loss In Illinois was computed for 1887, by 

 J. R. Dodj^e, Statistician of the IJ. S. Di!i>artment of Agriculture, at f 11,840,000. (See report of the 

 Commissioner of Agriculture for 1887, p. 50.) 



