MEXICAN" BEAN BEETLE IN THE SOUTHEAST. 



11 



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. 



Generation. 



Incuba- 

 tion 

 period. 



First 



Second 



Third 



Fourth 



Pupa- 

 tion 

 period. 



instar. 



instar. 



instar. 



instar. 



Days. 



Days. 



Days. 



Days. 



Days. 



Days. 



10 







6 



4 



8 



6 



6 



4 



3 



3 



6 



6 



6 



4 



3 



3 



6 



6 



6 



3 



3 



4 



8 



7 



Develop- 

 mental 

 period. 



First generation.. 

 Second generation 

 Third generation . 

 Fourth generation 



Days. 



1922: 1,407 EGG-TO-ADULT RECORDS. 



First generation . . 

 Second generation 

 Third generation. 

 Fourth generation 



8 



5 



4 



5 



8 



6 



6 



4 



4 



4 



S 



7 



6 



4 



4 



4 



8 



7 



7 







a 



7 



10 



12 



L/EE CyCLE 



oi/erw/a/tered 



BEETLES 



e/rst generat/oa/ 

 larv^s: 



E/RST GEA/ERAT/OA/ 

 BEETLES 



SEGOA/O GENERAT/OA/ 

 LARl/AZ 



SEGOA/D GEA/ERAT/OA/ 

 BEETLES 



Th'/RD GEA/ERAT/OA/ 

 LARl/AZ 



TR/R£> GEA/EBAT/O// 

 BEETLES 



EO//RT/V GEA/ERAT/OA/ 

 LARIAAZ 



EOC/RTH GEA/ERAT/OA/ 

 BEETLES 



BEETLES /A/ A//BERA/AT/OA/ ■■ 

 s4CT/l/E RE/7/OD — BEETLES <^&> 

 s4CT/VB PER/OD—LAA71&E <»► 



Fig. 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. 



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. K. Douglass. 

 Figure 7 gives the results of 1,590 egg-to-adult rearings, obtained 



