August, '22 



HOWARD: MEXICAN BEAN BEETLE 



Hibernation 



269 



Hibernation is the most pronounced characteristic of the family 

 CoccinelHdae which the Mexican bean beetle retains. The beetle 

 hibernates gregariously, as well as singly, but not in as large groups 

 or as compactly as Megilla maculata DeG., and many other coccinellid 

 species in California. Many individuals occur singly, and colonies 

 are not compact. At this writing, December 15, the beetles are still 

 congregating, as determined by marking beetles in colonies with differ- 

 ent colored waterproof marks, and observing them at intervals. Table 

 3 gives a brief summary of the data on hibernation. 



Taele 3. — Data on Hibernation of the Mexican Bean Beetle. 



303 



104 



199 



2,198 



1.221 I 



12 



Colonies of Marked Beetles 



"Destroyed by intruders. 



It will be noted that beetles are not only joining these colonies, but 

 some of the original beetles are leaving, and that the insect is not 

 completely dormant during the winter in northern Alabama. 



Field observations on an isolated farm proved that the spring migra- 

 tion from hibernation lasted at least as late as the middle of May. 

 March was exceptionally warm, averaging 7.7° F. daily excess above 

 normal. Field observations indicated that the peak of emergence was 

 late in April and early in May. 



The preferred winter quarters, so far as observed, are wooded slopes, 

 especially pine and oak growths. Well protected spaces, where branches, 

 tree trunks, or other obstructions have caused accumulations of leaves 

 or pine needles, are chosen. The beetles occur in this material at a 

 depth of an inch or more, seldom resting on the ground, and as yet 

 have not been found hibernating in the soil. The beetles ordinarily 



