MEXICAN BEAN BEETLE IN THE SOUTHEAST. ill 
TaBLE 3.—Summary of life history of the Mexican bean beetle at Birmingham, 
Ala., 1921 and 1922. 
[Average days of development.] 
1921: 2,019 EGG-TO-ADULT RECORDS. 
Incuba- | wirst | Second | Third | Fourth | PUPa | Develop- 
Generation. tion F F F F tion menta 
period. instar. instar. instar. instar. period. | period. 
Days. Days. Days. Days. Days. Days. Days. 
Hirst CeMeratlones ee esses 10 5 6 4 |, 8 6 39 
Second generation...----..----- 6 4 3 3 6 6 28 
Mhindsseneration saa+-sss-04--- 6 4 3 3 6 6 28 
Fourth generation.........----- 6 3 3 4 8 U 31 
1922: 1,407 EGG-TO-ADULT RECORDS. 
MinstseneratlOM.caese see ee ee ae 8 5 4 5 8 6 36 
Second generation.....-..----.- 6 4 4 4 8 7 33 
Third generation..---.......--- 6 4 4 4 8 7 33 
Fourth generation.........-.--- 7 5 5 7 10 12 46 
LY TIE OY GLE: 
OVER WIN TERED 
BEETLES 
FIAST GENERATION 
LAR VCE 
SEPT, 
Ba 
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Cee 
AUG 
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FIAST GENERATION mag 
BEETLES a 
‘SECONO GENEFA77 1c) 
LARUE ee ot : = | | 
eters [Cae ET 
reer 
SECOND GENERATION 
BEETLES 
THIRD GENERAT/ON 
LARK 
THIRD GENEFAT/ON 
BEETLES 
FOURTH GENERATION be) 
LARLE 
FOURTH GENERATION 
7H GEYERATION| | | a 
BSLETLES /N H/IBERNAT/ON a8 
ACTIVE PERIOD --BSEETLES Gi> 
ACTIVE FPERIOD--LARVE aye 
Fic. 6.—Life history of the Mexican bean beetle in an open-air insectary and field cages at Birmingham, 
Ala., during 1921. Based on 2,393 egg-to-adult rearings. 
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SEASONAL LIFE HISTORY. 
The discussions in this bulletin are based on observations covering 
only a two-year period in a restricted locality, which is too short a 
time to draw conclusions on many phases, especially since this study 
deals with an insect in a new habitat with a constantly increasing 
distribution. 
A large series of life-history experiments were performed during 
the two seasons, 1921 and 1922, and these have been condensed into 
charts. (Figs. 6, 7.) Figure 6 gives the results of 2,393 egg-to-adult 
rearings, obtained during the year 1921, chiefly by J. R. Douglass. 
Figure 7 gives the results of 1,590 egg-to-adult rearings, obtained 
