SEASONAL HISTORY. 



43 



and in the field, have shown that sugar and molasses, either in solution 

 or otherwise, have no attraction whatever for the weevil. Honey 

 exerts a very weak attraction, but not enough to be of any practical 

 use in control. In fact, it has not been found that any substance 

 exerts a special attraction for the weevil. The experiments have dealt 

 with many chemicals as well as plant decoctions. 



SENSE OF COLOR. 



A series of interesting observations on the color sense of the boll 

 weevil was made by Mr. C. R. Jones at Calvert and Victoria, Tex., and 

 Alexandria, La., in 1907. Tubes of different colors were placed in a 

 box, all with an equal amount of sunlight, and the weevils were given 

 food. The observations were made at intervals during the day, and 

 each time the weevils were all shaken back into the box. Table IX 

 shows the total number of weevils found at each color for the series of 

 observations and also the weighted average attractiveness. Fourteen 

 shades were used, but these may be grouped under eight colors. The 

 three most attractive shades were light-blue, dark-green, and light- 

 pink. While it is rather difficult to explain the results, it nevertheless 

 appears that there is some preference for certain colors on the part of 

 the weevil. 



Table IX. — Relative attractiveness of colors to the boll weevil. 



Color. 



Number of 

 observa- 

 tions. 



Number 

 of weevils 

 attracted. 



Average 

 attractive- 

 ness. 



Blue 



64 

 43 

 32 

 107 

 11 

 32 

 10 

 21 



461 

 261 

 123 

 411 

 24 

 29 

 5 

 6 



Per cent. 



7.2 



Green 



6.0 



Yellow 



3.8 



Red 



3.8 



White 



2.1 



Purple 



.8 



Orange 





Black 



.2 







MOVEMENTS ON FOOD PLANT. 



Various observations have been made to determine the amount of 

 movement of weevils at night. In July, 1904, at a mean temperature 

 of 76.3° F., Mr. A. C. Morgan found, in an aggregate of 134 weevil 

 nights, that eight weevils had moved but 25 times. Each weevil 

 had moved only once every six nights. On cloudy days weevils are 

 much more sluggish than on sunny days. Relative humidity influ- 

 ences the activity, but no definite observations on this point have been 

 made. 



The effect of temperature on locomotive activity may well be illus- 

 trated by a series of laboratory experiments conducted by Dr. A. W. 

 Morrill. A thermometer was passed through a cork and inclosed in 

 a test tube, which in turn was placed within a hydrometer cylinder 

 of sufficient depth to inclose it. Weevils were inclosed in the test tube 

 with the thermometer, and the temperature of the cylinder was varied 

 either by heating gently or by the use of ice water. Starting with the 

 thermometer at 64° F., the 10 weevils inclosed were found to move 

 slowly, half of them being quiet. As the temperature was gradually 



