MEXICAN" BEAN" BEETLE IN THE SOUTHEAST. 



13 



In the Southeast the beetles begin to leave their winter quarters in 

 the spring as early as late March and early April, or at about the time 

 when early garden beans are coming up. At Birmingham, Ala., this 

 date was March 22 in 1921, and April 6 in 1922. At Chattanooga, 

 Tenn., it was early in May in 1922. At Thomasville, Ga., the first 

 beetles emerged in the field March 27, 1922. One individual of a 

 colony of beetles, marked black, November 18, 1921 (Group 2, Table 

 6), was collected in a bean field April 22, 1922, three-fourths of a mile 

 from the place where it had spent the winter. The beetle is thus able 



L/FE CYCLE 



OI/ERW/A/TERED 

 BEETLES 



F/RST GENERAT/OA/ 

 LARl/AE. 



F/RST GENERAT/ON 

 BEETLES 



SECOA/D GENERAT/ON 

 LARYAZ 



SECOND GENERAT/ON 

 BEErLES 



TR/RD GENERAT/ON 

 LARU^E 



TR/RD GENERAT/ON 

 BEETLE'S 



FOL/RTR GENERAT/ON 

 LARVAE 



FO//RTN GENERAT/OA/ 

 BEETLE'S 



BEETLES /A/ R/BERNAT/OA/ 

 ACT/'SE PER/OD— BEETLES 



■ ■ 



ACTIVE PER/OD— LARl/A^ 

 EARLY RECORDS OF/92/ 



Fig. 8.— Seasonal life history of the Mexican bean beetle: Composite chart prepared from insectary records 

 and field observations during 1921 and 1922 near Birmingham, Ala. (eggs and pupae not shown) . Width 

 of bands shows relative abundance of beetles and larva? in the field. The insect is most abundant in 

 July. 



to make extensive flights at this time of the year. In New Mexico, 

 J. E. Graf found beetles hibernating 1\ miles from the nearest bean 

 field, and still farther from the most likely source. 



The spring migration lasts until early June, covering a period of 

 about two months. The beetle flies considerably all during the 

 summer from field to field and travels great distances. 



During August, 1921, and late July, 1922, the beetles became 

 restless and were often on the wing. During this period beetles a 

 week or more old fed less than earlier in the season. It is believed 

 that the greatest distribution occurs during the late summer and early 

 fall, but the spring migration is also undoubtedly of great importance. 



