410 Annals Entomological Society of America [Vol. IX, 



average of only three females was obtained in every thousand 

 flies caught. Traps were colored white, black, blue and orange, 

 but the size of the catches did not appear to depend on the 

 color of the trap. Traps placed under trees whose fruits 

 had a readily accessible supply of juice (Java plum) caught 

 the largest number of flies, but flies were often caught in traps 

 wired to trees not in fruit or which bore fruit not sought by 

 the flies. Petroleum oils containing comparatively large amounts 

 of volatile hydrocarbons were most readily sought while the 

 heavier burning and lubricating oils were less attractive. Oil 

 of citronella and turpentine had a very slight attraction, 

 cocoanut oil had none. Whale and fish oils were not visited 

 by the flies. The alluring properties of petroleum oils are 

 probably due to one or more of the volatile hydrocarbons or 

 to some of the impurities such as the sulphur or nitrogen 

 'constituents. While admitting that these attractive oils may 

 give off an odor which resembles that emitted by the female 

 fly, it is stated that the tropism may be one not associated with 

 sex. 



Chatterjee (1915) found that kusum oil from the berries of 

 the tree, Schleichera trijuga attracted nymphs and adults of 

 both sexes of a coried, Serinetha augur. A few drops of the oil 

 scattered about on any suitable object was sufficient to allure 

 large numbers of the bugs. The experiments were conducted 

 at Dehra Dun, India. 



I have recently published results of experiments on the 

 attractiveness of ammonia and certain other chemical com- 

 pounds to the house-fly Musca domestica L (Richardson, 1916, 

 a. and b.) . Ammonia from commercial ammonium carbonate and 

 ammonium hydroxide was attractive to females, but was 

 visited by few males. Eggs were deposited on the following 

 materials when ammonium carbonate was added to them: 

 acidulated horse manure (treated with dilute hydrochloric acid 

 so that all the volatile ammonia was converted into the non- 

 volatile ammonium chloride), moist timothy chaff, moist pine 

 sawdust and moist cotton. However cotton was scarcely 

 attractive without further addition of butyric or valerianic 

 acid. Horse manure was the most attractive, pine sawdust 

 and cotton the least. The house-fly apparently has some means 

 of discriminating between substances which can and those which 

 can not furnish food for its larvae. 



