BIOLOGY OF ARIZONA WILD COTTON WEEVIL. 7 



quiet period during which the bolls ripened, opened, and shed their 

 seeds. Then another crop of buds appeared and the same course 

 was repeated. In this manner as many as four crops of fruit were 

 produced by some of these lower plants and many produced three. 



Higher in the canyon channels and on the lower slopes (elevation 

 3,000 to 4,000 feet) the plants started to square shortly after the 

 1st of June and produced two or three crops before the end of the 

 season. They all began leafing out about the same time as the lower 

 plants just discussed. 



About the 1st of July the plants growing at about 4,500 feet started 

 squaring while those above 5,000 feet did not start until July 30 or 

 later, and produced only one crop. 



From this is seen the extreme variation in the fruiting period of 

 the plant. This grouping by altitude is of course only approximate 

 because the conditions (moisture, exposure, etc.) vary greatly at the 

 same altitude in different locations. 



The active period of the plant will probably vary with the different 

 years according to climatic conditions. The winter of 1913-14 was 

 exceptionally mild and consequently some of the lower plants may 

 have started blooming earlier this season than is usual. 



Regardless of the previous activity of the plants, the last crop of 

 fruit (produced during August and September) is always the largest 

 and blooming extends over a longer period at this time. Most of the 

 plants stopped blooming during the latter part of September though 

 quite a few continued blooming into early October. 



The appearance of the weevils from hibernation is very scattering 

 during the early spring months. The first record of emergence dur- 

 ing the spring of 1914 was an individual noted in a branch of Agua 

 Caliente Canyon at about 3,000 feet altitude on May 10. Following 

 this a few were found active here and there in the mountains, but 

 they were not common until later in the season. 



These early individuals fed upon the squares and bolls present, 

 and produced a few progeny in the latter. The resulting weevils 

 emerged after a normal developmental period and aided in the 

 infestation of the large crop of fruit in August and September. 



The general emergence of the weevils began shortly after the first 

 of July and by the middle of August nearly all weevils had emerged. 

 These were all quite active on the plants after this time. During the 

 past season the writer did not note a single weevil breeding in the 

 buds of Thurberia, although considerable feeding upon them was 

 observed. This is directly contrary to the conditions found by Mr. 

 Pierce in August, 1913, when he observed the weevils breeding 

 abundantly in Thurberia buds in both the Santa Catalina and Santa 

 Rita Ranges. This discrepancy in records may be due to some 

 differences in the seasonal conditions. 



