99 



of corn, March 2 and May 5, and two lots of cotton, April 29 and 

 July 26. With this arrangement the corn could be cut when it was 

 no longer needed and the entire space given up to cotton later in the 

 season. The screen prevented the escape of any moths or larvae, but 

 left them subjected to very neai'l}^ normal weather conditions. It also 

 served to keep out predaceous enemies and many of the larger para- 

 sites, thus providing against possible depletion from these sources, 

 and at the same tinae preventing access to the plants by moths outside 

 of the cage. 



The cage was stocked with a large number of eggs on May 9, and 

 the forthcoming generation of bollworms was traced in its develop- 

 ment. The following table, compiled from dail}^ records, summarizes 

 very briefly the average growth of each generation: 



Table XL. — Generations of bollworms, Paris, Tex., 1904. 

 [Dates are for Paris, Tex., latitude about 33° 45'.] 



Brood. 



Moths 

 out. 



Eggs de- 

 posited. 



Larvae 

 hatched. 



Larvae 

 one- 

 fourth 

 grown. 



Larvae 

 one-half 

 grown. 



Larvae 

 three- 

 fourths 

 grown. 



Larvae 



full 

 grown. 



Pupae. 



1(50 days). 



2 (35 days). 



3 (31 days). 



4 (48 days). 



5 



May 6 

 June '25 

 Aug. 3 

 Sept. 3 



Oct. 22 



May 9 

 June 27 

 Aug. 5 

 Sept. 10 



May 14 

 June 30 

 Aug. 7 

 Sept. 13 



May 21 

 July 7 

 Aug. 10 

 Sept. 18 



Mav 26 

 July 11 

 Aug. 14 

 Sept. 23 



June 1 

 July 14 

 Aug. 17 

 Sept. 25 



June 5 

 July 16 

 Aug. 20 

 Sept. 27 



June 8. 

 July 18. 

 Aug. 22. 



Oct. 2; in hiberna- 

 tion. 



















The first record of injury to cotton was on July 6, due to young 

 larvse of the second brood. The damage rapidly increased until, on 

 July 12, some sixty squares and a few young bolls had been destro\^ed. 

 A few da3^s later, after the larvae from corn had pupated, the corn was 

 removed and late cotton planted in its place. The injury of the two 

 following generations was confined entirely to the early planted cotton, 

 as the late cotton was not squaring in time to be subject to attack. 

 The fourth brood was represented by but few individuals, due possibly 

 to the fact that the greater number of the pupae from the third genera- 

 tion had remained in the soil to hibernate. This conclusion was 

 strengthened by the appearance of a moth on September 22, evidently 

 a belated specimen of the generation due to emerge on September 3. 

 The few larvae pupating early in October also passed into hibernation 

 with the pupae of the previous generation still in the soil. 



LABORATORY EXPERIMENTS. 



In working out the life cj^cle of the boUworm in the laboratory at 

 ditferent times during the summer it was found by Mr. Girault that 

 the growth and transformations undergone by individuals indoors 

 closely coincided with the data obtained from the field work. The two 

 sets of experiments were run along together, and the agreement 



