MEXICAN BEAN BEETLE IN THE SOUTHEAST. 3 



Term., where the insect was not known to occur until 1921, the same 

 situation occurred in 1922, one year after the insect reached that 

 region. (Figs. 1,2.). By the fall of 1922 practically no beans 

 were growing about Chattanooga. Serious damage also occurred 

 about Atlanta and other points in northern Georgia, and in many 

 sections of eastern Tennessee. 



DESCRIPTION. 



The Mexican bean beetle is a robust, hard-shelled insect of hemi- 

 spherical form bearing eight black spots on each elytron or wing 

 cover. (Fig. 3; PL II, A.) Typical adults measure about one- 

 fourth to fire-sixteenths inch in length and one-fifth to one-fourth 



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Fig. 3. — Adults of the Mexican bean beetle, showing variations in size and marking. 



inch in width, and when fully mature are copper-colored. Newly 

 emerged specimens are light lemon yellow. Males are distinguished 

 from females by a notch in the posterior abdominal segment, this 

 notch being absent in the females. Males average slightly smaller, 

 but many are as large as females. 



The eggs are small, about one-twentieth of an inch long, orange- 

 colored, and are laid in masses of from 40 to- 60 on the under sides 

 of the bean leaves. 



The larvae, on hatching from the eggs, are orange-colored, and 

 are covered with long branched spines. (Fig. 4; PI. I, A.) They 

 grow rapidly and become about one-third inch long and half as wide 

 before pupation takes place. (PI. II, B.) 



The pupa is almost the size of the beetle, is yellow, and is attached 

 to the leaf or object on which it pupates by the last larval skin, 

 which is white and spiny and covers the posterior abdominal seg- 

 ments. (PI. Ill, A, B.) 



