October, '15] CLAUSEN: APHID-FEEDING COCCINELLID.^ 



487 



SULFUR AS AN INSECTICIDE 



By George P. Gray 

 (Withdrawn for publication elsewhere.) 



A large number of photographs illustrating the work of the Medi- 

 terranean fruit fly were exhibited by Mr. E. A. Back. 

 Session adjourned, 12 m. 



Afternoon Session, August 10, 1915 



The session was called to order at 2.15 p. m. by Mr. H. F. Wilson^ 

 president of the Pacific Slope Association of Economic Entomologists. 



President Wilson: We will now listen to a paper prepared by 

 Mr. C. P. Clausen which will be read by Mr. S. W. Foster. 



A COMPARATIVE STUDY OF A SERIES OF APHID-FEEDING 



COCCINELLIDiEi 



By C. P. Clausen, University of California Citrus Experiment Station, 

 Riverside, California.^ 



Among the beneficial insects of California as well as elsewhere, the 

 Coccinellidse hold high rank as aphid and scale feeders. In order to 

 determine the relative efficiency of some of the more important forms, 

 a study of eight of the principal aphid-feeding species of this state was 

 made at Sacramento during the season of 1913, and completed at 

 Berkeley and Riverside in 1914. The species under observation were: 

 Hippodamia convergens Guer., Hippodamia ambigua Lee, Coccinella 

 californica Mann., Coccinella trifasciata Linn., Olla oculata Fabr., 

 Olla abdominalis Say., Cycloneda sanguinea Linn., and Adalia bipunc- 

 tata Linn. 



At the time the investigations were undertaken, an extensive series 

 of tests were made to determine the most satisfactory type of breeding 

 cage for use in the laboratory. By far the most satisfactory results 

 were secured by confining the individuals under observation in plain 

 three-inch vials with cotton stoppers. The stoppers were covered 



^ Paper No. 19. Citrus Experiment Station, College of Agriculture, University 

 of California, Riverside, Cal. 



