from a flight screen in a field where cotton stubble had been plowed under about a 

 month previously. 



These facts indicate that A^ grandis does not hibernate in this part of Mexico, 

 which is a desert plateau about 3,700 ft. above sea level where cotton is raised 

 by means of irrigation. Annual rainfall is less than 9 inches. 



1932 - Cartwright, O. L. Insect pests and related matters. S. C. Expt. Sta. 1931-32 Rpt. 

 45:65-79. 



More adults of the cotton weevil emerged from hibernation in cages placed in 

 a sheltered ravine than in those in an exposed situation on a hill, and oak leaves 

 and pine needles gave better protection in the cages than maize stalks. An aver- 

 age of 11.6% of all the weevils placed in the cages in October 1931 emerged. 



1934 - Cartwright, O. L. Entomology. S. C. Expt. Sta. 1933-34, Rpt. 47:56-64. 



"Cotton boll weevils ( Anthonomus grandis Boh.) placed in cages in 1933, 

 2.53% survived in winter and emerged between 9th April and 5th July 1934. More 

 adults emerged from hibernation in cages placed in an exposed situation on a hill 

 than in those in a sheltered ravine. 



"As a result of the combined attack of A. grandis and P. seriatus , little fruit 

 was set on the upper third of the cotton plants in one locality." 



1935 - Gaines, R. C. Cotton boll weevil survival and emergence in hibernation cages in 



Louisiana. U. S. D. A. Tech. B. 486, 28 p. 



A study of the hibernation of Anthonomus grandis Boh. was carried out at 

 Tallulah, La., over the 15-year period 1915-16 to 1930-31, with the exception of 

 the winter of 1926-27, and in 17 cooperating laboratories in various States during 

 the last 7 years of the investigation. The tests were made in screen wire cages 

 of a uniform size. A standardprocedure, whichis described, was followed through- 

 out, one variable being introduced into each series of tests. 



The average winter survival for the whole period under all cage conditions at 

 Tallulah was 1.22%. The percentages at most of the other stations were higher be- 

 cause more favorable shelters were used and more of the weevils were placed in 

 the cages after October 6th. The figures that follow were obtained at Tallulah. 



In a study of the effect of time of entering hibernation, the highest survival 

 (2.55% to 2.92%) was among weevils placed in cages between October 20th and 

 November 18th. None of those placed in cages before September 7th survived. 



Among various materials provided for shelter, the highest survivals oc- 

 curred in maize stalks (1.99%), followed by Spanish moss (1.66%), Spanish moss 

 and cotton stalks (1.44%), sawmill debris (1.36%), and oat straw (1.34%). A much 

 lower rate of survival occurred in a number of other materials and combinations. 

 During the winters of 1925-26 onwards, the percentage surviving in Spanish moss 

 was 0.57% in cages placed under standing timber and 0.88% in an open field. 



In a study of the relation of survival to winter weather conditions, the only 

 significant correlations were with minimum temperatures. Coefficients of cor- 

 relation between survival and the number of times the temperature fell below 

 32°, 30°, 24°, 22°, 20°, and 18°F , respectively, were found to be significant. 

 Those between survival and the number of times the temperature ranged from 

 18° to 20° and from 1° to 17°F., and that between survival and the minimum 

 temperature for the winter were also significant. The weighted average per- 

 centage for the 4 years that the minimum temperature was 20°F., or higher, was 

 3.96%, as compared with 0.29% for the remaining years. Of the total number of 

 weevils surviving, 15.7% emerged in March, 22.9% in April, 39.7% in May, 21.4% 

 in June, and 0.3% in July. The emergence period for the different years ranged 

 from 47 to 127 days, with a weighted average of 117 days. The extremely short 

 period of emergence was during the years of very low survival. Emergence 

 extended into July in only 4 years. 



1935 - Gaines, R. C. Boll weevil activity during normal hibernation period at Tallulah, 

 La. J. Econ. Ent. 29(6): 1 096- 1 099, 1 fig., 2 ref. 



Observations made in Louisiana, from December 21 to the end of February 

 during 6 winters, on the relation between temperature and the activity of adults 

 of the boll weevil hibernating in cages. 



144 



