OF WASHINGTON, VOLUMK XV[, I'M I 27 



Male grandis were placed with female tfun-ln'rin which were 

 isolated when extracted from their 1912 pupal cells in the latter 

 part of August. The three females thus used began oviposition 

 in 2, 2 and 4 days after being placed with the males on cotton 

 squares. During the month of September they deposited 87, 92 

 and 137 eggs each, with an average of 3.5 eggs per female per day. 

 The developmental period of the progeny determined up to Octo- 

 ber ] averaged 18.5 days for 4 males and 3 females, all unusually 

 small. 



Male thurberite were placed with known infertile female f//v/m//.< 

 and these deposited, during September, 7 ( .) and 25 eggs each, with 

 an average of 1.9 eggs per female per day. The development;;! 

 period of the progeny determined to October 1 averaged 19 days 

 for 5 females and 5 males. 



Typical thurberiie pairs were placed on cotton squares and bolls. 

 The development in bolls has not yet been determined but is suc- 

 cessful. On squares the females deposited during September, 71. 

 71, 90 and 171 eggs each, with an average of 4.5 eggs per female 

 per day, which was better than the average in either cross. 

 The developmental period of the progeny determined to October 

 1 averaged 17.2 days for 7 females and 12 males. 



In discussing the two preceding papers Mr. Hunter referred 

 to the biological and possible economic importance of the obser- 

 vations that had been made. 



It has been known for a long time that the principal barrier the 

 cotton boll weevil encounters in the United States is dryness of 

 climate. This has prevented the invasion of important cotton 

 producing areas in western Texas. The Arizona weevil has evi- 

 dently acquired an ability to withstand such conditions. This 

 is a strong indication of the plasticity of the species. Another in- 

 dication of this is the fact that the Arizona weevils adapted them- 

 selves perfectly to the conditions of the humid country at Victoria, 

 Texas, as soon as they were transported to that place, and is fur- 

 ther evidenced by the ready change from Thurberia to cotton when 

 transported to a new region. 



The ability of the Arizona weevil to maintain itself in the face 

 of extremely arid conditions shows its possible great economic 

 importance. If it should by accident, or otherwise, be establish- 

 ed in the arid country of western Texas it would probably main- 

 tain itself. If this should happen there would be a continuou- 



