12 
BULLETIN 902, 17. S. DEPARTMENT OF AGRICULTURE. 
Owing to the extreme delicacy of the larvae, it was impossible to 
rear large numbers at any one time. The small numbers of beetles 
which developed showed little disposition to breed and it was not 
possible to determine the number of generations occurring annu- 
ally from any given "stock," or lot of specimens. The rearing 
records obtained, however, indicate the probability of three genera- 
tions occurring annually in Otero County, Colo. 
In Tables II, III, and IV records of the observed generations of the 
western cabbage flea-beetle in 1916 are given: 
Table II.- 
-First generation of western cabbage flea-beetle. 
Item. 
First 
genera- 
tion. 
Adults captured and confined 
First eggs deposited 
First eggs hatched 
First larva? pupated 
First adults developed. . 
Egg stage 
Larval stage 
Pupal stage 
Total duration 
1916. 
Apr. 10 
14 
24 
May 23 
June 3 
Days. 
Table III. — Second generation of the western cabbage flea-beetle 
Item. 
Beetles confined 
First eggs deposited. . . 
First eggs hatched 
First larvae pupated . . . 
First adults developed 
Egg stage 
Larval stage 
Pupal stage 
Total duration . . 
Second 
genera- 
tion. 
1916. 
June 24 
26 
July 1 
19 
25 
Days. 
29 
Table IV .—Third generation of the western cabbage flea-beetle. 
Item. 
Third 
genera- 
tion. 
Beetles confined 
1916. 
Aug. 8 
First eggs deposited 
12 
First eggs hatched 
19 
First larva? pupated 
Sept. 10 
First adults developed . 
20 
Days. 
7 
Larval stage 
22 
Pupal stage 
10 
Total duration 
39 
