548 



JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 8 



or with varying strengths of the extract to determine the weight of 

 the chicken killed by a certain amount of poison, also to determine the 

 age limit of the chickens killed. 



The results m-ay be summarized as follows: 15 to 20 rose chafers 

 are sufficient to cause the death of a chicken a week old. From 25 to 

 45 rose chafers are usually necessary to kill a three-weeks-old chicken. 

 While some nine-weeks-old chickens have been killed by eating rose 

 chafers, only one ten-weeks-old chicken was killed in these experi- 

 ments. In the crop of this chicken there were 96 undigested rose 

 chafers counted in post mortem examination. 



The chickens feed upon the insects ravenously, being attracted by 

 their sprawly appearance and usually within an hour after eating they 

 begin to assume a dosing attitude, later leg weakness shows and the 

 chicken usually dies within 24 hours of having eaten upon these insects, 

 or begins to improve after this time. 



In less than five per cent, of the deaths convulsions occurred. Post 

 mortem examinations showed no abnormal condition of the organs. 

 In order to exclude the possibility of arsenical poisoning due to the 

 rose chafers having probably fed upon leaves that had been sprayed, 

 tests were made by a chemist for arsenic, but no evidence of arsenic 

 was found. Intravenous injections also were made in these experi- 

 ments, extracts for injection being made from forty grams of rose 

 chafer and sixty grams (cc.) of a salt solution having a specific gravity 

 of .9 per cent. This extract was put in a centrifuge for five minutes, 

 the extract drawn off in a pipette and filtered in vacuo. 



Three cc. of this extract was injected into a 690 gram rabbit in- 

 travenously and this died in six minutes. Another rabbit, weighing 

 1,435 grams, died after an injection of four cc. of this extract in three 

 and one-quarter minutes. A small 610 gram rabbit, when injected 

 with two and one-half cc, died in fifty-five seconds after injection, 

 and a large 1,450 gram rabbit died in two hours and thirty-five min- 

 utes after being injected with two cc. Other rabbits were injected 

 and killed by this extract but further work needs to be done to de- 

 termine what is a lethal dose for rabbits and also experiments in feed- 

 ing rabbits per os will be taken up next summer. 



As near as the writer can determine, the rose chafers contain a 

 neuro toxin, that has a direct effect upon the heart action of both 

 chickens and rabbits and is excessively dangerous as a food for 

 chickens. 



Owing to the fact that the insect feeds upon such a large number 

 of plants it seems essential that chickens be kept in mowed fields and 

 away from yards having grape vines and any flowering shrubs during 

 the month when rose chafers are most numerous, especially during 

 years when rose chafers are particularly abundant. 



