258 THE MONTHLY BULLETIN. 



is not essential. About two ounces of the sirup should be placed in 

 cadi bag; which should then be tacked to the trunk of the tree, after 

 folding, as shown in the illustration. Several experimental plots of one 

 acre each in citrus orchards have been provided with poison bags. In 

 the plots where the poison has been out for a month the ants are 

 difficult to find mi the trees, while in the check plots in the same 

 orchards they are present in enormous numbers. 



At the present time the poison method looks much more promising 

 than banding. The latter method is expensive and when not done by 

 experienced men is ineffective. The effects of dust and hot sun, 

 together with the growing of cover crops in the orchard, make satisfac- 

 tory banding a difficult and expensive proposition. The poison method 

 has none of these difficulties to contend with and its results should be 

 more or less permanent. 



If, after the present experiments are carried through the entire 

 season, it is demonstrated that we can effectively combat the ant by 

 this means, a general campaign should lie carried on against the pest, 

 with the cooperation of the county horticultural commissioners. There 

 is still time to attempt the subjugation of the Argentine ant, at least 

 in restricted orchard districts, if it can be done by means of poison 

 bags, and such an attempt would certainly be justified in view of the 

 possibility of the insect as an indirect orchard pest. 



DARK CURRANT FRUIT FLY IN CALIFORNIA. 



Rhagoltis ribicola, Doane. 



By Henry H. P. Severin, California Agricultural Experiment Station. 



In the summer of 1915, Mr. E. P. Van Duzee, together with the 

 entomological field class of the University of California summer school, 

 spent about five weeks in the Sierra Nevada Mountains and added over 

 six thousand mounted insects to the university museum. Among the 

 flics collected was a single specimen of the dark currant fly (Bhago- 

 letis ribicola, Doane), which is of considerable economic importance in 

 the state of Washington. In order that there might be no question of 

 doubt as to our identification of this pest, this trvpetid was sent to 

 Professor R. W. Doane (2) who described the species. Professor Doane 

 states, "I have a single specimen of Rhagoletis ribicola from Pullman, 

 Washington, and your specimen seems to agree witli it in every respect." 

 The dark currant fly was captured near Cathedral Lake, in a valley on 

 the eastern slope of Mount Tallac, at an altitude of about 7,500 feet, 

 Tahoe, California, on July 6, 1915. 



