83 



APPARENTLY FAVORABLE CONDITIONS FOR HIBERNATION. 



In December, 1902, a series of experiments was started to test the 

 influence of various conditions upon the successful hibernation of 

 weevils. Owing to the writer's absence from Victoria examinations 

 could not be made at intervals, as would have been desirable. But 

 at the middle of April, 1903, careful examinations were made to ascer- 

 tain the shelter in which live weevils were found. In the preparation 

 of hibernation jars several inches of dirt was placed at tlie bottom, 

 and above that a variety of such rubbish as was thought might 

 tempt the weevils to shelter. Dead banana leaves, hay, cotton leaves, 

 dry bolls, squares, etc., were among the things used as rubbish. As 

 several of these were placed in each jar the weevils had an oppor- 

 tunity^ to choose their shelter. Among the 39 which lived through 

 the winter, 19 were found in the banana leaves, 7 in hay, 5 in dry 

 cotton leaves, 4 were buried in dirt, 3 were on the surface of the 

 soil, and 1 was hiding in an open boll. It appears, therefore, that 31, 

 or 80 per cent of the 39 live weevils, were found in what may be 

 termed "leaf rubbish." It was noted also that 25 of the survivors 

 passed the winter out of doors in various locations, while 13 were 

 under shelter indoors. Of the weevils placed out of doors all but 

 one lot were protected from the rain. The 15 weevils contained in 

 the jar which became wet all died, while but few of the jars which 

 were drj^ failed to show a live weevil in the spring. Leaf rubbish and 

 dryness appear to be favorable factors in successful hibernation. 



PERCENTAGE OF WEEVILS HIBERNATING SUCCESSFULLY. 



Naturally the percentage of weevils living through the winter will 

 depend largely upon favorable climatic conditions and the accessibil- 

 ity of suitable shelter. It would be utterly impossible to determine 

 this question under actual outdoor conditions, and our inferences 

 must be drawn solely from percentages found to survive un'der cage 

 conditions. In the laboratory tests referred to in the preceding topic 

 356 weevils were used. Of these, 240 were brought from the fields at 

 the middle of December, 1902. Among these weevils, 38, or 15.8 jjer 

 cent, survived. The remaining 116 weevils were all adult after Sep- 

 tember 25, 1902, and had been kept under observation in the labora- 

 tory. One single weevil, adult November 12, was the sole survivor of 

 this lot. Since the weevils brought from the fields in the middle of 

 December would be a correct average of those entering hibernating 

 conditions, we may disregard tlie laboratory specimens in drawing 

 our conclusions. The conditions offered would seem to have been 

 favorable, and when this is the case out of doors it appears that about 

 one in six of weevils found in the field at hibernation time may pass 

 the winter successfully. This seems a very high jjercentage, but 

 when we consider the numbers of hibernating weevils often occurring 



