APPENDIX. 433 



well within the mark, but many investigators have stated that the 

 potato beetle is single brooded in the northern part of its range. 



Dr. Otto Lugger, in the report of the Minnesota Agricultural 

 Experiment Station, issued by the University of Minnesota in 

 1895, states that the usual number of eggs laid by each female is 

 about six hundred. Assuming that he is correct in stating that 

 the potato beetle in Minnesota is three brooded, the number pro- 

 duced by one female a year under the conditions noted above 

 possibly might reach one hundred and forty-six million. ' 



A. T. Weed, entomologist of the Mississippi Agricultural Ex- 

 periment Station, stated in 1897 that the potato beetle deposited an 

 average of about five hundred eggs, but sometimes one thousand. 

 It seems probable that the number of eggs laid by each female was 

 greater during the advance of the insects across the country from 

 the west than it now is.^ 



Later investigations have led others to doubt whether the in- 

 sect ever produces three full broods in a season. Dr. J. B. Smith 

 claims two generations and sometimes a partial third in New 

 Jersey. Chittenden (1907) states that two is the normal number of 

 generations, and that Tower has observed that this number is a 

 remarkably constant generic character. 



The latest statement by an entomologist that has come under 

 my observation, regarding the number of eggs laid by the Colorado 

 potato beetle, is that of Dr. E. Dwight Sanderson, dean of the 

 College of Agriculture of West Virginia University and director of 

 the West Virginia Agricultural Experiment Station. His state- 

 ment is to the effect that each female lays an average of about five 

 himdred eggs during the course of a month, that throughout the 

 territory where the beetles are most injurious there are two gen- 

 erations a year, that further south there is evidence of a partial, 

 if not complete, third generation, and that in the northern part 

 there is but one generation a year.^ 



Assuming that Sanderson is correct, and the average number of 

 eggs laid by each female is five hundred, the progeny would num- 

 ber five hundred for the year where the insect is single brooded; 

 where there are two broods the number would be two hundred and 

 fifty thousand; with two and one-half broods the number would 

 be sixty-two million, five hundred thousand, which is close to 



' Report of Minnesota Agricultural Experiment Station, Bulletin No. 43, December, 

 1895, p. 158. 



' Report of Mississippi Agricultural Experiment Station, Bulletin No. 41, March, 1897, 

 p. 188. 



^ Insect Pests of Farm and Garden, by E. Dwight Sanderson, 1912, p. 293. 



