immediately witn a small atomizer; the housefly maggots and tendi- 

 pedid larvae, on the other hand, were not anaesthetized before being 

 sprayed. The treated insects were fed alive to fish conditioned in 

 daphnia ponds, aquaria, or battery jars containing hard water. The 

 small, medium, and large aquaria used contained 25, 27, and 44 liters 

 of water, respectively. The sprayed insects were fed inaividually 

 to the fish and were usually devoured immediately. Water temperature 

 readings were taken daily at about 8:00 a.m., and 4:30 p.m. 



The following spray formulations were used in these experiments: 



Formula 1: 2 pounds of 50 percent wettable QDT powder and water 

 to make 1 gallon. 



Formula 2» 1 pound of DDT, 2 pints of xylene, and fuel oil 

 No. 2 to make 1 gallon. 



Formula 3: 1 pound of DDT, 3180 ml. of a napthenic solvent 

 (PD-544-B), and fuel oil No. 2 to make 1 gallon. 



Consumption by the Bltiegill of Inaects Sigayed with DDT in Oil 



The following experiment was set up to ascertain Trtiether fish 

 gorging on poisoned insects for one day and receiving untreated food 

 on succeeding days were affected by the poison. On June 18, 1947, 20 

 bluegills in excellent condition and averaging 82 ram., in length were 

 isolated in each of three concrete daphnia ponds (25 by 8 by 3 feet). 

 Hie fish in two ponds were fed all the adult houseflies sprayed with 

 formula 3 that they would eat in a day. After fasting for 3 days, the 

 fish in one pond devoured an average of 13 treated flies per day com- 

 pared with 16 in the other pond, and the fish in the control pond took 

 an average of 12 untreated flies each. later the fish in all ponds 

 were fed untreated food periodically. "Die temperature of the water 

 during the experiment averaged 71° F. No mortality resulted in any 

 of the ponds by the end of 14 days, when the experiment was concluded. 

 In a previous experiment CSurber 194^) 25 fingerling and 25 adult blue- 

 gills in each of two ponds devoured 3,988 and 4,037 sprayed flies, 

 respectively, over a period of three days, and all the fish survived, 

 as did those in the control pond. 



A second experiment was aimed to determine the inunediate effect 

 on fish after devouring treated insects, and the ultimate effect on 

 fish When some of them subsequently were fasted and ottiers well fed. 

 Each of 12 aquaria was stocked v/ith three bluegills averaging 78 ran., 

 in length. In eight of these, fish were given all the houseflies 

 treated with. DDT in oil (formula 3) that they would devour in one day. 

 The fish in the other four aquaria were fed untreated flies. The 



