506 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 14 



in a cement block. This block was molded in a coffee can and after the 

 surface was smoothed with a trowel somewhat and the cement hardened, 

 two coats of white paint were applied. A covering of felt was placed on 

 the bottom of the stand. 



A thordarson, type D, three-way step-down transformer, primary 

 voltage 110, secondary voltage 6 — 8 — 14, 60 watt capacity, was used in 

 order to attach the lamp to the ordinar}^ 110 volt alternating current. 

 Wherever direct current is used some other form of resistance will be 

 necessary. It is safest to install a fuse block with fuse plugs of low 

 amperage to protect the transformer. As many as three of these lamps 

 may be attached to this transformer. The cost of this lamp depends 

 upon the kind of transformer used which in turn depends upon the 

 number of lamps desired and the candle-power of the bulbs which are 

 used in the lamps. A rheostat may be used to regulate the intensity of 

 illumination if this is desired. The retail price, at Charlottesville, 

 Virginia, of three lamps, including one transformer as shown in figure 12, 

 was $25.50 or and average of $8.50 per lamp, complete. 



The chief advantages of this lamp are as follows: it furnishes a 

 powerful light; develops very little heat; is economical in the use of 

 electrical current; is easy on the eyes; is easily adjusted and installed 

 and at the same time is comparatively inexpensive. These lamps have 

 proven most satisfactory for our taxonomic work and they have also been 

 used advantageously for photographic work with the Leitz Microscopic 

 Camera. 



THE ARGENTINE ANT BUILDS EARTHEN PROTECTIONS 

 FOR MEALY BUGSi 



By E. O. EssiG 



One of the most serious problems in connection with the control of 

 many of the serious scale insects infesting orchard trees and other plants 

 in California is the Argentine Ant, Iridomyrmex humilis Mayr, which 

 so valiantly keeps away the natural enemies of the coccids. 



Wherever the so-called biological method of pest control is employed, 

 it is first necessary to take steps for the control of this ant in order to 

 allow the proper freedom, and development of the parasites and predators. 

 For not only does the ant keep away the small hymenopterous parasites, 

 but violently and effectively attacks the larger larvae of the ladybird 



'Contribution from the Division of Entomologv, University of California, Berkelev, 

 California. Dec. 15, 1919. 



