October, '13] EWING: OREGON COCCIXELLIDiE 405 



numbers feeding upon the pollen of various plants. In searching for 

 such food, there frequently is a tendency for large numbers to move in 

 certain directions or to collect upon certain very much desired flowers. 

 However, there does not appear to be any fixed migration accom- 

 panied by such gregarious habits as are found for example in the case 

 of some of the species of blister beetles, Meloidae. 



By the middle of August (which here is the hottest and dryest part 

 of the year) the coccinellids begin a definite migration. They, almost 

 of one accord, quit the hot dry valleys and move upward, many of 

 them never stopping until the highest point for miles around is at- 

 tained. Thus, last September I found thousands of them on the very 

 summit of Mt. Chintimini, the highest point in the Coast Range 

 Mountains. Here in these higher altitudes the coccinellids move about 

 and swarm many times. As soon as winter has set in they have 

 settled in their permanent hibernating quarters. These consist of 

 pockets under large stones, rubbish, or under leaves or logs. There is 

 a strong tendency for the different species and varieties to segregate 

 themselves in their winter quarters. Thus in many pockets of Hippo- 

 damia convergens Guerin will be found all or over 90 per cent of the 

 typical form, i. e., the form with thirteen spots on the elytra. Other 

 pockets will contain individuals all or the most of which are spotless 

 forms of H. convergens Guerin. I have found that there is sometimes 

 a mixing of species in the hibernating quarters, thus frequently a few 

 individuals of H. spuria Leconte will be found with H. convergens 

 Gue'rin and vice versa. 



The coccinellids pass the winter without food, and are, for long 

 periods at least, perfectly quiescent. That some of our species can 

 pass the winter hibernating at the lower levels I have proved by exper- 

 ments, the mortality, however, is very great unless they are kept in 

 artificially cooled quarters. 



Emergence of Adults in Spring 



There is some variation among the different species in regard to the 

 time of emergence in the spring. At Corvallis, a valley town 230 

 feet above sea level, I have the following records for the spring of 1913. 

 The dates given represent the first recorded observation of an active 

 individual out of doors: 



Chilocorus hivulnerus Muls February 10. 



Hippodamia convergens Guerin (spotless form) April 11. 



Adalia bipunctata Linn April 14. 



Hippodamia convergens Guerin (typically marked) April 16. 



Hippodamia convergens Guerin (with some spots) April 17. 



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