16 



BULLETIN 124, U. S. DEPARTMENT OF AGRICULTURE. 



states that the species activates during 1 the summer months from 

 June to November. 



In the year 1910, in the Imperial Valley of California, there were 

 four distinct generations up to July 15. The fourth generation, how- 

 ever, was almost entirely exterminated by the disease before men- 

 tioned, and, following this ; later generations became so largely con- 

 fused that it was impossible to separate them, since, unfortunately, no 

 series of generation cages were then in use for this purpose. The 

 first generation in 1913 covered the period from March 15 to April 

 30 ; the second generation from May 1 to May 28 ; the third genera- 

 tion from May 28 to June 20; and the fourth generation from June 

 20 to July 15. It seems quite probable that there were at least 

 three generations during the rest of the season. As shown in Table 

 III, during the year 1912, at Tempe, Ariz., there were six genera- 

 tions, adults of hibernating forms appearing in March and adults 

 of the fifth generation disappearing in October, while a few adults 

 of the sixth generation appeared during warm periods of the winter 

 months. 





Table III.- 



—Generations c 



fthe 



%lfalj 



a caterpillar, 



Tempe, 



Ariz 



, 1912} 







Eggslaid. 



Eggs 



hatched. 



bo 

 <D 



O 03 



T3 

 CP 



C3 



ft 





'c3 



> 



% . 







"3 

 ft 



3 



ft . 



ft'd 



oo 



CO ft 



CO 





Gen- 













-m 



era- 

 tion. 













-)J co 



ft 





-J-3 CO 



3 





+3 CO 





CD 



CD aS 



Sfft 





o 





CD 







a* 



> 





a 1 



'3 





a 



a 



£ § 





03 





03 









c3 





CD 



■n 







5 







fi 



£ 



fi 





£ 



Hi 



a 





H) 



<^ 





h1 



EH 



s 



<: 





1912. 











Days. 







Bays. 







Days. 



Bays. 





°F. 



1st... 



Mar. 24 



Many. 



/Apr. 



7 

 8 



12 

 31 



141 

 15/ 



May 



11 



34 



May 



19 



8 



56 



1 17 females. 

 to0 males... 



J-63.5 



2d ... 



May 27 



36 



May 



31 



36 



4 



June 



18 



.18 



June 24 



6 



2S 



[2 females.. 

 \1 male 



J83.75 



3d.... 



June 25 



Many. 



June 



28 



Many. 



3 



July 



13 



15 



July 



19 



5 



23 



|3 females . . 

 \2 males 



JS6.5 



4th... 



July 22 



Many. 



July 



25 



Many. 



34 



Aug. 



12 



18 



Aug. 



19 



7 



284 



IX female.. - 

 \1 male 



J84.5 



5th... 



Aug. 23 



6 



Aug. 



26 



6 



34. 



Sept. 



9 



16 



Sept. 



19 



10 



294 



(3 females . . 

 13 males 



jso.o 



6th... 



Sept. 23 



Many. 



Oct. 



3 



Many. 



5 



Nov. 



IS 



45 





T 



hese hibernated. 



64.0 



i The first half of this ta'le does not rive duration of time elapsing between emergence and oviposition. 

 2 Date here is the day the last ones issued. 



PERIODS AND DURATION OF GENERATIONS. 



Bays. 



First generation, Mar. 24 to May 27 64 



Second feneration, May 27 to June 25 29 



Third generation, June 25 to July 22 26 



Fourth generation, July 22 to Aug. 23 33 



Fifth generation, Aug. 23 to Sept. 28 38* 



Sixth generation, Sept. 28 to pupae in hibernation. 



Mr. T. Scott Wilson, working at Tempe, secured records during 

 the year 1913 of three distinct generations from late March to the 

 latter part of July, his observations thus corresponding fairly well 

 with those of the writer during the previous year. The dates of 

 the three generations were as follows : First brood, March 27 to May 

 20; second brood, May 20 to June 23; and third brood, June 23 to 



