BULLETIN 422, U. S. DEPARTMENT OF AGEICULTUEE. 



not counted as eggs. The following data have been selected from 

 the data concerning these three females : 



Table II. — Egg-laying records of three females of the eggplant tortoise beetle. 



Female A. 



Female B. 



Female C. 



Egg laying begun 



Last eggs deposited 



Total number of eggs deposited 



Greatest number deposited in one day 

 Average number deposited in a day . . 



July 7 



Aug. 16- .. 



268 



10 



7 



July 7. 

 Aug. 26. 



269 

 12 

 5 



July 7. 

 Aug. 24. 



231 

 11 

 5 



NUMBER OF GENERATIONS. 



With a continuous food supply available during the spring, sum- 

 mer, and fall, it is apparent that several generations, perhaps five^ 

 will develop during this time at Baton Rouge. The minimum life 

 cycle in the insectary during June can be summed up as follows : ^ 



Days. 



Period from appearance of first adult to date first eggs were laid 9 



Length of egg stage 4 



Length of larval stage 12 



Length of pupal stage 2 



Total 27 



During the same period the egg and larval stages were completed 

 in 16 days in outdoor cages, corresponding to the minimum time 

 required in the insectary. As larvae were observed in the field as 

 early as May 10 and as late as October 20, there is a strong proba- 

 bility that, under ideal conditions, there may be five generations in 

 a year. After the first generation, individuals in all stages are found 

 in the field at the same time, so that it is hardly possible to determine 

 the number of generations that develop under natural conditions, 



ENEMY. 



The only insect enemy of this tortoise beetle that has been found 

 is an egg parasite which has not been determined as yet. So far as 

 observed this species, which was first noted at Baton Rouge during 

 August, destroys only a small percentage of the eggs. 



EXPERIMENT WITH ARSENICALS. 



During May larvse were causing sufficient injury to small eggplant 

 at Baton Rouge to warrant the application of poison to the plants, 

 and an experiment with arsenate of lead and arsenite of zinc was 

 conducted, the application being made with a compressed-air sprayer. 

 From this experiment the following summary has been made : 



i Somes (7) foiuid in Missouri that from eggs laid in July a longer period was required for the develop- 

 ment of a generation. 



