16 
BULLETIN 124, U. S. DEPARTMENT OF AGEICULTUEE. 
states that the species activates during the summer months from 
June to Xovember. 
In the year 1910. in the Imperial Valley of California, there were 
four distinct generations up to July 15. The fourth generation, how- 
ever, was almost entirely exterminated by the disease before men- 
tioned, and. following this, later generations became so largely con- 
fused that it was impossible to separate them, since, unfortunately.no 
series of generation cages were then in use for this purpose. The 
first generation in 1913 covered the period from March 15 to April 
30 : the second generation from May 1 to May 28 ; the third genera- 
tion from May 28 to June 20 : and the fourth generation from June 
20 to July 15. It seems quite probable that there were at least 
three generations during the rest of the season. As shown in Table 
III. during the year 1912. at Tempe. Ariz., there were six genera- 
tions, adults of hibernating forms appearing in March and adults 
of the fifth generation disappearing in October, while a few adults 
of the sixth generation appeared during warm periods of the winter 
months. 
Table III. — Generations of the alfalfa caierpiVcr, Tempe, Ariz., 1912} 
u 
Eggs laid. ' Eggs hatched. g 
i 
— 
"5 
> 
i 
- c z 
S3 
Gen- 
era- 
O 3 
& 
ra 
at 
1 
tion. 
& 
& 
s-s 
*j 
--- 
*3 M 
— — JL r 
,Q 
-'- 
& 
a 
2 
a 
% 
> 
^ 
E 
¥ 
a a 
s 
55 
c= 
p 
a 
§ 
© 
B> 
■cJ 
© 
o 5 
> — 
fi 
£ 
A 
£ 
^ 
- 
- 
< 
hJ 
i- 
£ 
< 
1912. 
Days. 
Days. 
Days. 
Days. 
°F. 
1st. . . 
liar. 24 
Many. 
Apr. 
8 
12 
31 
141 
15/ 
May 11 
34 
May 19 
8 
56 
/17 females. 
\30 males... 
J63.5 
2d ... 
May 27 
36 
May 
31 
36 
4 
June IS 
18 
June 24 
6 
28 
p. females.. 
\l male 
}S3. 75 
3d.... 
June 25 
Many. 
June 
28 
Many. 
3 
July 13 
15 
July 19 
5 
23 
(3 females.. 
\2 males 
JS6.5 
4th... 
July 22 
Many. 
July 
25 
Many. 
3* 
Aug. 12 
18 
Aug. 19 
7 
28* 
fl female.. . 
\lmale 
JS4.5 
5th... 
Aug. 23 
6 
Aug. 
26 
6 
3§ 
Sept. 9 
16 
Sept. 19 
10 
294 
(3 females.. 
13 males 
}so.o 
6th... 
Sept. 2S 
Many. Oct. 
3 
Many. ; 5 
Nov. IS 
45 
These hibernated. 
64.0 
1 The fust half of this taMe does not rive duration of time elapsing betvreen emergence and oviposition. 
2 Date here is the day the last ones issued. 
PERIODS AND DURATION OF GENERATIONS. 
Days. 
... 64 
.. 29 
.. 26 
.. 33 
.. 38* 
First feneration. Mar. 24 to May 27 
Second feneration. May 27 to June 25 - 
Third generation, June* 25 to July 22 
Fourth generation, July 22 to Aug. 23 
Fifth generation, Aug. 23 to Sept. 28 
Sixth generation. Sept. 28 to pupae in hibernation. 
Mr. T. Scott Wilson, working at Tempe, secured records during 
the year 1913 of three distinct generations from late March to the 
latter part of July, his observations thus corresponding fairly well 
with those of the writer during the previous year. The dates of 
the three generations were as follows : First brood. March 27 to May 
20: second brood. May 20 to June 23: and third brood. June 23 to 
