THE RED SPIDER ON COTTON. 



MATING. 



Almost immediately upon becoming adult, the red spiders mate 

 and begin egg laying. The males seem to recognize unfertilized 

 females with ease. The first eggs are frequently deposited on the 

 same day upon which the transformation occurs from the last 

 nymphal to the adult stage. 



PARTHENOGENESIS. 



Experiments conducted with unmated female red spiders clearly 

 prove tliat they are normally capable of laying eggs, which in tuiTi 

 hatch and develop into mature individuals. No tests, however, have 

 been successfully conducted to determine the sexual fertility of the 

 latter. 



GENERATIONS. 



The season of 1911 at Batesburg, S. C. was one of unusual drought 

 and heat, and there w^ere about 17 generations between March 11 and 

 November 5. The time required for a single generation varied from 

 85 days in March and early April to 10 days throughout most of 

 June, July, and August, and to 25 days in the greater portion of 

 October and early November. During the same period of 1912 at 

 Batesburg only 16 generations were produced. The 1912 season 

 was late in commencing, was somewhat cooler than that of 1911, and 

 more showers occurred. From April 24 to September 25 there was 

 small variation in the time required for the generations — averaging 

 about 11 days. Two generations developed each in 9 days, which is 

 less than was required for any brood in 1911. Thirty days was re- 

 quired for the October-November generation. The following table 

 presents the duration of each stage of each of the 17 generations 

 for 1911 : 



Table I. — Dcrcloiniiciit of ycncrations of tlie red .sijider on cation in 1911. 



Gener- 

 ation. 



Period covered by generation. 



Incuba- 

 tion 

 period. 



Larval 

 period. 



Nymph 



(1) 

 period. 



Nymph 

 period. 



Ov {po- 

 sition to 

 adult. 



1 

 2 

 3 

 4 

 5 

 6 

 7 

 8 

 9 

 10 

 11 

 12 

 13 

 14 

 15 

 16 

 17 



Mar. 11 to Apr. 14. 

 Apr. 15 to Apr. 29. 

 Apr. 30 to May 13. 

 May 14 to May 25.. 

 May 26 to June 6.. 

 Juiie 7 to June 17.. 

 June 18 to June 27. 

 June 2S to July 7 . . 

 JulvS to July 18.. 

 July 19 to July 28.. 

 July 29 to Aug. 7.. 

 Aug. 8 to Aug. 17.. 

 Aug. IS to Aug. 29. 

 Aug. 30 to Sept. 9. 

 Sept. 10 to Sept. 24 

 Sept. 25 to Oct. 10. 

 Oct. 11 to Nov. 4.. 



Average 



Days. 

 13 

 6 

 6 

 5 

 5 

 4. 

 4 

 4 

 4 

 4 

 4 

 4 

 5 

 5 

 5 



Days. 

 9 

 3 

 3 

 3 

 3 



2.5 

 2 



2 



2 



2.5 



2 



3.5 



3 



Days. 

 6 

 3 

 3 



Days. 

 7 

 3 

 2 

 2 

 2 

 2 

 2 

 2 

 2 

 2 

 2 

 2 



2.5 

 2 



3.5 

 4 

 5 



Days. 



3.1 



2.8 



