57 



Thomas, Cyrus. — Temperature and Rainfall as Affecting the 

 Chinch Bng. — Periodicity in its Increase. (Am. Ent., Oct., 

 1880, V. 3, pp. 240-242. Abstract of article, in Prairie 

 Farmer, Sept. 10, 1881.) 



Chronological data graphically represented by map showing 

 relations of chinch-bug outbreaks in Illinois and adjoining por- 

 tions of Iowa and Missouri, to weather conditions. Author 

 began his investigations by ascertaining the annual average 

 of rainfall from 1840 to 1877, and then noted the variation of 

 each year from this average, representing these variations by 

 curves. Taking this diagram as basis of discussion, calls atten- 

 tion to the fact that the series of years appears to be divided 

 into cycles of seven. For example, counting backward from 

 1876 to 1840, the rainfall every seventh year seems to have been 

 above the average, and this septenary period seems divided into 

 periods of four and three years, the ternary period ranking first 

 as to rainfall and the quaternary second. Next considers the 

 relation of the rainfall to the appearance of chinch bugs, and re- 

 garding it as generally admitted that two successive dry years are 

 necessary to the development of these insects in injurious num- 

 bers, he finds the chronological history of the species to be fairly 

 conformable to his theory of periodicity. In closing he says, 

 "The high temperature of 1854, '7J, and '74, together with the 

 diminished rainfall, furnish the key to the cause of the great de- 

 velopment of the chinch bug during these years." 



J[ohnson], B. F. — Oar Correspondence. (Cultivator and Coun- 

 try Gentleman, Oct. 28, 1880, v. 45, p. 692.) 



Champaign Co., Oct 19. Losses from chinch bug this year are 

 trifling, "but there are already indications that it will appear in 

 force on next year's crops." 



Forbes, S. A.— The Food of Birds. (Bull. 111. State Lab. Nat. 

 Hist., V. 1, No. 3 (1880), pp. 113, 115, 121, 124.) 



Chinch bugs were found in the food of the catbird and brown 

 thrush, and in that of a single robin. 



1881. 



Thomas, Cyrus. — Questions Answered. (Prairie Farmer, Jan. 8, 

 188L) 



Gives winter habits of chinch bug. 



Thomas, Cyrus. — Relation of Meteorological Conditions to In- 

 sect Development. (Trans. 111. State Hort. Soc. 1880, n. s., 

 V. 14, pp. 89-99.) [Shorter article under the same title 

 (essentially an abstract of the above) in Farmers' Review,. 

 Jan. 13, 1881, v. 6, p. 30.] 



Speaks of continual increase of insect enemies of agriculture 

 due to extension of cultivation and to contact of cultivated areas. 

 Accounts for oscillations of injurious insects by reference to 



