LITERATURE FOR 1914 ON THE BEHAVIOR OF 

 SPIDERS AND INSECTS OTHER THAN ANTS 



C. H. TURNER 



Sumner High School, St. Louis, Mo. 



TROPISMS 



1. Chemotropism. — By attaching shallow pans, containing 

 kerosene, to the branches of trees, Severin and Severin (77) 

 were able to catch large numbers of the Mediterranean fruit 

 fly (Ceratitis capitata). Out of 5,490 flies trapped in eighteen 

 days only thirty were females. As these authors say, "It is 

 certainly peculiar that the Mediterranean fruit fly plunges into 

 kerosene to its own destruction." By using pans of four different 

 colors (white, black, blue and orange) they demonstrated that 

 the number of flies secured was not determined by the color 

 of the pan. They think it highly probable that the sense of 

 smell plays an important role in attracting the flies, and admit 

 that it might be a positive chemotaxis due to one or more hydro- 

 carbons or to the impurities of the petroleum oils. "Again, 

 the hydrocarbons of the oil may act as an anesthetic, and stupify 

 the insects whenever they remain within its influence." Neither 

 of these suppositions, however, accounts for the preponderance 

 of males. For a period of eight months these flies were trapped 

 daily. During that time only three victims out of every thousand 

 were females. Admitting that the proof is not conclusive, these 

 investigators believe that the kerosene emits a scent similar to 

 " some sexual odor of the female which in natural conditions 

 serves to guide the male to her." This harmonizes with Hew- 

 lett's interpretation* of the reaction of Dacus zonatus to the 

 oil of citronella. 



In another paper (78) these two investigators have discussed 

 the relative attractiveness of vegetable and petroleum oils for 

 the Mediterranean fruit fly. 



2. Hydrotropism. — In two different species of water beetles, 



* Hewlett, F. H. The Effects of Oil of Citronella on Two Species of Dacus. 

 Trans. Ent. Soc, London, 1912, pt. II, pp. 412-418. 



415 



