14 BULLETIN 1243, U. S. DEPARTMENT OF AGRICULTURE. 
At least as early as the first week in October the beetles begin to 
fly to woodlands and enter hibernation. The majority have left the 
fields by the time the daily mean temperatures reach 55° to 60° F., 
but a few remain until heavy frosts occur. 
Fewer eggs are laid after the middle of August. Larve are cor- 
respondingly scarce, but all stages are present until killing frosts 
occur. 
Life for long pone without food, as shown by starvation tests, 
indicates that the species is remarkably prepared for adverse con- 
ditions when host plants may be unavailable. One adu!t lived 102 
days without food in the presence of moisture. In general they 
Fic. 9.—A typical infested bean plant photographed in the field shown in Plate VI, B. 
succumb to starvation after 5 to 15 days, but a few live considerably 
longer. After starving for 68 days, 19 beetles out of 50 survived and 
entered hibernation November 22, 1922. An adult with food lived 
121 days. The average life of 34 pairs used in experiments was 58_ 
days, the females averaging 50 days and the males 68. 
FOOD PLANTS. 
The Mexican bean beetle is primarily a bean pest (Pl. VI, A, B; 
text fig. 9), attacking by preference the common beans, including 
bush and pole varieties of snap beans, pinto, navy, and Lima beans, 
and tepary beans, all of the genus Phaseolus. It can subsist, however, 
on a number of other plants, and in many instances has severely 
damaged cowpeas and soy beans. About Birmingham, Ala., in 1921, 
and about Chattanooga, Tenn., in 1922, some fields of cowpeas were 
