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was seen carrying a plant-louse, usually a young one, down the 

 trunk. WHiat the fate of these plant -lice was we were unable to 

 determine. Perhaps they were intended to serve the purpose of 

 starling new colonies on other plants but more likcl)^ they were 

 taken to the home of the ants to serve as food, for ants feed 

 on plant-lice when the appetite is upon them, just as man keeps 

 cows both for milk and meat. I am, however, inclined to doubt 

 the statements of man)- naturalists who speak of the carefully 

 conducted hx'gicnic aphis-dairying industries of ants. In coun- 

 tries with suitable climatic conditions, as, for example, California, 

 aphides arc very plentiful and widely distributed upon a great 

 variety of plants, and ants cannot well avoid running across them 

 ■on hawthorns, roses, chenopodiums, thistles, plum-trees and a 

 .host of other plants. 



The starting of new colonics of Aphis seems wholly unneces- 

 sary, yet who is there to know all of the factors concerned in 

 the ant commercial competition ? Be that as it may, the ant is 

 not the only organism that finds the Aphis iw\ available economic 

 victim. We noted several species of beetle of the ladybird 

 ■variety, quite numerous and quite constantly present in the grass 

 >{Poa) and on other plants near the infested hawthorns. The 

 brown-winged ladybird {Hippodaiuia cotivcrgois) was found to 

 feed very voraciously upon the plant-lice. It was roughly con- 

 jectured that one ladybird would destroy (feed upon) its own 

 weight of plant-lice in the course of one night. Some of these 

 handsome little beetles were found basking in the morning sun, 

 evidently digesting a heavy meal. Others were busily engaged 

 with their breakfast. This ladybird i)romises to be of economic 

 value in the extermination of plant-lice. A report on its pos- 

 sible uses is about to be published h\- the Dept. of Agriculture 

 of the University of California. .Another beetle (dark green 

 elytra with black spots) {Diabrotica Soror) was also quite con- 

 stantly present and seemed to feed ujjon Aphis, although it also 

 feeds upon the black fungus on the hawthorn antl the di.sea.sed 

 plant-lice above referred to. A liglitning bug {Podabrus priiiii- 

 asus) is also an occasional visitor and feeds upon plant-lice. The 

 ants and beetles pay no attention to each other, evidently bccau.se 

 they reali/.e the fact that tlicy are incapable of harming each other. 



