BIOLOGY OF AEIZONA WILD COTTON WEEVIL. 21 



deposition to adult emergence of 31 days. At the close of the ex- 

 periment all bolls were opened and the contents examined. Almost* 

 all of them showed not the slightest signs of weevil larval work 

 and only one weevil stage was found. This was a pupa found 

 November 9 in a boll which received an egg October 14. 



Thurberia buds were tested in the same manner several times 

 during the season but always with negative results. In fact, it was 

 found exceedingly difficult to induce the weevils to deposit in them. 



TESTS OF CAGED WEEVILS ON GROWING PLANTS. 



ON THURBERIA PLANTS. 



In order to study the activities of the weevils upon Thurberia 

 plants in the field, a large cage was arranged over a plant growing 

 under cultivation at the ranch. (PI. II, fig. 1.) The plant was 

 nearly 5 feet tall and well laden with buds, blooms, and bolls. 



Two male and two female weevils were removed from hibernation 

 cells in the Thurberia bolls August 30 and fed upon Thurberia buds 

 and leaves in captivity until September 14. They were then released 

 in the cage with the growing Thurberia plant. 



On September 17 two small buds had fallen to the ground with 

 feeding punctures. On the 21st 6 small bolls, 3 buds, and 2 blooms 

 had fallen, all fed upon by the weevils. Several of the fallen bolls 

 and many still hanging on the plant contained egg punctures. 



On October 2 it was noted that a very large proportion of the 

 bolls of the plant had been punctured and many contained eggs or 

 larvae, but very few squares had been attacked. 



The plant stopped blooming about October 10, and at this time 

 many of the bolls had the purplish color characteristic of those 

 infested. No bolls were on the ground, and a rather violent shaking 

 of the plant failed to cause any to drop. On October 31 one male 

 weevil was found active on the roof of the cage. A very careful 

 examination of the plant and trash in the cage failed to reveal any 

 other weevils. The infested bolls were still hanging on the plant. 



On January 2, 1915, all bolls were removed from this plant and 

 the cage examined for weevils. No adults, either alive or dead, 

 were found in the trash or on the cage walls. All bolls were exam- 

 ined and the following contents noted: 271 bolls taken from the 

 plant were examined; 123 were uninjured, 115 were injured but 

 contained no weevil stages, 30 contained live adults, and 3 con- 

 tained 1 dead larva, 1 dead pupa, and 1 dead adult, respectively. 

 Eight bolls found on the ground were examined and 6 were found 

 to show signs of weevil injury, but no stages were present. Of the 

 total of 279 bolls examined, 154 had been injured more or less by 

 the weevils, or an infestation of 55.2 per cent. This indicates what 

 was certainly a great activity on the part of the two females. 



