94 BULLETIN 1243, U. S. DEPARTMENT OF AGRICULTURE. 
maximum emergence, estimated from observations, probably — 
occurred from May 10 to May 27, which is three weeks later than at 
Birmingham, Ala., where cages were placed at 600 feet above sea 
level, at 33° 31’ N. latitude. The insect at the latitude and altitude 
of Lookout Mountain remains in hibernation from 74 to 8 months. 
TABLE 9.—Data on hibernation cage at Chattanooga, Tenn., on Lookout Mountain, 
winter of 1921-22. 
Beetles collected at Birmingham, Ala. | Beetles emerged. 
Date. Number. Date. Number. 
OCR Oren cae ree en ae ene ee ae Bee 60000), AspG: 26.2 32.200 sees sais ao Sere Seen 37 
OCHO Re ret ee eee ae es ees 12 (O00 May LG coats Sirs elie aise ee ime pe 465 
Mia Vb SSE Ss os Sel eI re ber 585 
May 2 Tact eett es. Se 2 eee eee 629 
JUN ON ake n cone ee ee Aan eee eee 24 
MPotalksars 410k. Asee srr ee eee | 18, 000 Ota = See eee, Sa ee 1,740 
Beetles transported to Chattanooga and placed in | Next observation was June 29, when there were no 
cage Oct. 11. living beetles in the cage. 
Percentage Sunvivall = 2555-52525 ee eee 920 
HIBERNATION AT THOMASVILLE, GA. 
The isolated infestation at Thomasville, Ga., offers an interesting 
comparison of the habits of the Mexican bean beetle at a low alti- 
tude (about 300 feet above sea level) and more southern latitude 
(30° 54’ N.) with those at the higher altitudes and more northern 
latitudes of Birmingham, Ala., and Lookout Mountain, Tenn. 
Hibernating habits under natural conditions at Thomasville, 
Ga., during the winter of 1921-22 were very similar to those about 
Birmingham, Ala. Because of the lighter infestation and the rela- 
tively smaller acreage of bean plantings, adults were not so numerous. 
An area of several square miles surrounding the city was included 
in the study of hibernation. A total area of 4,823 square feet, 
representing 718 searches, was examined carefully. Of 152 adults 
observed in hibernation, 69 per cent were found in a colony com- 
prising 105 beetles. These were found at the base of a large oak, 
erowing in contact with a large gum tree. The beetles were dis- 
tributed from 1 to 3 inches below the surface in oak and cum leaves. 
Close by was a garden which had contained pole Lima beans which 
had been destroyed by the beetle the previous summer. 
In searching for hibernating bean beetles many adults of the 
related squash beetle® were also observed in hibernation, often 
under identical conditions, side by side, under leaves on the ground. 
The well-known habit of the squash beetle of hibernating in crev- 
i es in the bark of trees has not been observed in the case of the bean 
reetle. 
A hibernation cage like those mentioned above was used at Thomas- 
ville. (See Table 10.) In 1921 the majority of the beetles left 
the fields late in October, but a few were present as late as Decem- 
ber. The first issuance from hibernation observed in the field was 
March 29, 1922, but, as noted in Table 10, emergence began February 
28 in the cage and continued until June 3. The survival was 30 
5 Bpilachna borcalis Fab, 
