ENTRANCE INTO HIBERNATION. 15 



TIME OF ENTERING HIBERNATION. 



Before discussing the question of the time at which weevils usually 

 ' ' enter hibernation ' ' it seems desirable to explain the sense in which 

 that term is used. The action of the weevils in securing shelter from 

 approaching cold is not intelligent. It is probably true that the}^ 

 have no such sense of sight as we commonly understand from the 

 use of that word and that their selection of shelter is not at all 

 guided by that sense. We mean by this that a weevil on a cotton 

 plant can not see at any distance shelter which might be attractive 

 to it and thereupon fly from the plant to the shelter. It is true that 

 cold nights with a temperature between 40° and 50° F. succeeded 

 by warm still days, such as occur commonly in the fall, do seem to 

 stimulate the weevils to an unusual activity both in fiiglit antl in 

 crawling. It may be true that they have an instinctive knowledge 

 of the approach of temperature conditions from which they must 

 secure shelter, but it is ■ also true that many weevils remain active 

 upon plants for some time after the plants have been destroyed by 

 frost and frequently until several weeks after other individuals 

 have entered hibernation. In speaking of entering hibernation, 

 therefore, we mean the entrance of the weevils upon a period of 

 comparative if not complete inactivity. Their action in securing 

 shelter is gradual and governed primarily by the degree of protec- 

 tion from the cold which they may receive. If early in the season 

 a weevil accidentally finds shelter which gives it exceptional pro- 

 tection from the cold it will likewise be exceptionally protected from 

 heat, and therefore less likely than are other less fortunate indi- 

 viduals to resume its activity upon warm days. If at first the 

 shelter which weevils find is but slight, they will be easily influenced 

 by succeeding warmth, and in another period of activity will be 

 likely to find better protection. Their flight upon warm days un- 

 doubtedly leaves large numbers of them outside of the cotton fields, 

 where they are as likely to fuid favorable shelter as within the fields 

 themselves. 



From this explanation it will be understood that it is rarely pos- 

 sible to indicate by a single date the time when weevils enter hiber- 

 nation. It may be better expressed as a period within the limits 

 of which a large majority, though possibly not all, weevils may seek 

 shelter. Naturally this time varies according to the seasonal tem- 

 perature conditions, so that in one locality it may occur several 

 weeks earlier in one season than in another. It is also evident that 

 differences in temperature conditions due to latitude or altitude will 

 cause a similar variation in the time when weevils enter hibernation. 

 In the following paragraph are given the approximate dates which 

 have been determined for this event at various localities since 1902. 



