9 2 4 
Journal of Agricultural Research 
Vol. V. No. ao 
1915. This was an indoor experiment, and the beetles had been kept in 
a warm room during this entire period. In the field the first adults 
were observed in the insectary garden May 4, 1915. It was quite cold 
during that period compared with the earlier season of 1914. 
SUMMARY AND CONCLUSIONS 
In the authors* experiments in 1914 in the District of Columbia eggs of 
the Colorado potato beetle were laid almost immediately after the first 
overwintering beetles were collected in copulation in the spring. These 
overwintering beetles fed continuously until September 7, when the last 
one died. The adults of the first generation upon emergence fed for a 
short time; some of them went into hibernation, but most of them laid 
eggs for a second generation. Likewise, some adults of the second gen¬ 
eration hibernated, while others laid eggs from which adults of the third 
generation developed. Dr. Chittenden has stated 1 that in the course of 
his investigations he was not able to get the beetle to breed more than 
twice in a season without a period of estivation; but from the few eggs 
that were laid in the second generation the authors were able to rear 
the species through three generations without a resting period. 
In 1908 Popenoe 2 made experiments with this insect in tidewater 
Virginia, and reared it through three generations, but all the beetles of the 
third generation died. In this experiment the heat was still greater 
than in Washington in 1914, and the insects were not isolated in large 
numbers and were not well fed, which accounts for the dying of the 
third generation. 
The entire developmental period from egg to adult was passed, as 
previously stated by Dr. Chittenden, in approximately four weeks. 
Particular attention is called to the fact that the female, far from 
laying the small number of eggs attributed to this species, is capable of 
laying, in one case under actual observation, 1,879, while a second female 
deposited 1,301 eggs. The former record exceeds any hitherto published, 
so far as known. It should be stated, however, that during 1913 Mr. 
W. O. Ellis, 3 of the Iowa Agricultural Experiment Station, obtained 
from a single female of the species a total of 1,686 eggs, and that Messrs. 
Girault and Zetek 4 took 1,578 eggs from a single beetle. 
From the experiments reported herein it is evident that there are 
three completed generations of the Colorado potato beetle in the District 
1 Chittenden, F. H. The Colorado potato beetle (Eeptinotarsa decemlineata Say). U. S. Dept. Agr. 
Bur. Ent. Circ. 87, p. 8-9. 1907. ‘ 
a Popenoe, C. H. The Colorado potato beetle in Virginia in 1908. U. S. Dept. Agr. Bur. Ent. Bui. 82, 
pt. 1, 8 p. t 2 pi. 1909. 
8 Ellis, W. O. Leptinotarsa decemlineata Say. In Jour. Econ. Ent., v. 8, no. 6, p. 520-521. 1915. 
4 Girault, A. A., and Zetek, James. Further biological notes on the Colorado potato beetle, Eeptino- 
tarsa 10-lineata (Say), including observations on the number of generations and length of the period of 
©viposition. II, Illinois. In Ann. Ent. Soc. Amer., v. 4, no. x, p. 74. 1911. 
