24 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



varieties were taken to Stockholm, Sweden, by Mr. A. N. Caudell, 

 and compared with the type of Anthonomus grandis. 'On account 

 of Mr. Caudell's careful comparison the usual form of this species, 

 known as the Mexican cotton boll weevil, must be known as Antho- 

 nomus grandis grandis Boheman and the Arizona wild cotton, 

 or Thurberia weevil, as Anthonomus grandis thurberice Pierce. 1 



The experiments described in this paper have been carried out 

 along several different lines. The principal results have been the 

 ascertaining of the ability of the two varieties to interbreed and 

 produce fertile offspring, and the working out of the developmental 

 period for certain seasons of the year. 



The first weevils were obtained from the Santa Rita Mountains, 

 Arizona, in May, 1913, and were extracted from their cells in the 

 Thurberia bolls, at WashiDgton about May 15, and then shipped 

 with fresh Hibiscus foliage to Victoria, Tex., where they were re- 

 ceived May 20'. A second sending was received from the same 

 locality in Arizona about September 1. 



The weevils extracted in May were divided into three lots, the 

 first being male and female thurberice, the second thurberice females 

 placed with grandis males, the third grandis females placed with 

 thurberice males. 



Three pairs of typical thurberice were placed on cotton but they 

 did not take readily to the new food plant. Only eight eggs were 

 deposited and these by a single pair. From the eight eggs 

 just two weevils matured. The period of development was 19 

 days, identical with that for typical grandis at that season. In 

 83 weevil-feeding days, 60 feeding punctures were made, or 0.7 

 per day with 3 the maximum. In 30 weevil-oviposition days, 

 only 8 eggs were laid, or 0.2 per day. 



Inasmuch as the thurberice individuals received in May were 

 together, there was a possibility of fertilization. They had just 

 been extracted from their hibernation cells and had not fed when 

 received at Victoria. In the experiment with female thurberice 

 and male grandis no eggs were laid by either female until June 2, 

 12 days after being placed with the grandis males. Copulation 

 was observed in one pair on the second day of the experiment. 

 Each pair was actually observed in copula ^hree times and the 

 actual number of copulations was probably considerably greater. 

 In 161 weevil-feeding days, 461 feeding punctures were made, 

 with the average per individual 2.8 per day. In 64 weevil-ovi- 

 position days 245 eggs were laid, wiuh an average of 3.8 per day 

 and a maximum of 10. Eggs were obtained from June 2 to July 

 3 from these two females. The offspring were bred from June 26 



1 Journ. Agric. Research, vol. i, no. 2, November, 1913. 



