258 University of California Publications. [Entomology 



Ten adults during a fifteen-day period consumed an indi- 

 vidual maximum of 661 aphids and a minimum of 414, with an 

 average for the series of 500 aphids. Upon a daily basis this 

 would be 34.0 aphids per day. During the period the number 

 eaten daily ranged from 16 to 62, which is considerably lower 

 than the record of Hippodaniia convergens, a condition not to be 

 expected from the relative sizes of the individuals of the two 

 species. This numerical relationship is not evident in the case 

 of the larvae, and the difference may in all probability be at- 

 tributed to the variation in climatic conditions existing at Sacra- 

 mento and at Riverside, California. In this experiment the rose 

 aphis (Macrosiphwm rosae) was used exclusively. 



Total 661 609 529 465 524 436 428 414 574 468 



Average 44.0 40.6 35.2 31. 34.9 29.0 28.5 27.6 38.2 31.2 



Coccinella trifasciata Linn. 



This species is not of any great importance in California be- 

 cause it occurs only in limited numbers in most sections, though 

 in the San Francisco Bay Region it may be found in very con- 

 siderable numbers, at times to an extent even greater than Hip- 

 podamda convergens. The adults ordinarily pass the winter 

 singly, hidden away in bunches of grass, leaves, and in other 

 protected places. This is one of the first species to appear in the 



