14 BULLETIN 1336, U.S. DEPARTMENT OF AGRICULTURE 



Table 8. — Length of -pupal stage -of 'the green clover worm 1 



No. 



Date of 

 pupation 



Date of 

 emerg- 

 ence 



Number 

 of days 



No. 



Date of 



pupation 



Date of 

 emerg- 

 ence 



Number 

 of days 



1 



May 20 

 ...do 



May 30 

 May 31 

 June 27 

 June 28 

 June 29 

 June 30 

 July 1 

 July 10 

 July 12 



...do 



...do 



July 13 



10 

 11 

 8 

 9 

 7 

 8 

 8 

 9 

 11 

 10 

 7 

 8 



13 



Aug. 12 



Aug. 24 

 Aug. 23 

 Sept. 8 

 Sept. 15 

 Sept. 21 

 Oct. 28 

 Oct. 29 

 Nov. 3 



12 



2 



14 



Aug. 14 



9 



3 



June 19 

 ...do 



15 



Aug. 25 

 Sept. 1 

 ...do 



14 



4 



16 



14 





June 22 

 ...do 



17 



20 



6 



18 



Oct. 4 

 Oct. 6 

 Oct. 14 



24 



7 



June 23 

 July 1 



...do 



July 2 

 July 5 



...do 



19 



23 



8 



20 



20 



9.. 



10 







12. 1 



11 . 









24 



12 









7 













i The data for the months of June and July were obtained by F. M. Moody. 

 SUMMARY OF LIFE CYCLE 



The egg-laying period of the moth may last for a period of 11 

 days or more, the egg hatching during the summer and early fall in 

 about 4 days. The larval period lasts about 23 days, in the course 

 of which the caterpillar molts five times and spends approximately 

 two days as a prepupa inside the cocoon. The pupal period lasts 

 from 7 to 24 days, except when lengthened by hibernation. Table 9 

 gives the average lengths of the different stages. 



Table 9.- 



—Summary of duration of stages of development of the green clover worm 



Stage 



Average 

 period 



Egg 



Bays 

 3.88 



Larva. 

 Pupa 



Total 



22.84 

 12.10 



SEASONAL HISTORY 



NUMBER OF GENERATIONS A YEAR 



During the season of 1916 at Knoxville, Tenn., four distinct 

 generations were found to occur. Certain heavily infested alfalfa 

 fields on the farm of the State Agricultral Experiment Station were 

 visited every few days, and records were kept of the varying abund- 

 ance of the different stages of this species. Parts of these fields were 

 standing throughout the season, which eliminated the interference 

 of cutting with the development of the generations. Figure 14 



APRIL 



KM JUHE 



JULY 



AUGUST 



SEPTHT3ER 



OCTOBER 







_<<<^^ 



^ 



S^W^S 



^ 



^-rrr-TT-TT 



^^$^ 



















fcage. 



e stages. 











A,\\\\\\\\V\I Artnl+. r 





MHHBHHNH icirr.atur 



Fig. 14. — Diagram showing the number of generations of the green clover worm during the year 1916 at 



Knoxville, Tenn. 



