April, '15] ENTO^IOLOGISTS' PROCEEDINGS 247 



Sarcophagids were reared almost to the exclusion of oviparous forms, 

 the latter consisting principally of Muscina stahulans (Fall). While 

 the number of experiments was too hmited to permit of definite con- 

 clusions, they did indicate that where surface excreta and that from 

 surface privies was concerned, the Sarcophagids apparently prevented 

 the oviparous species from breeding in any great numbers. This may 

 be due to the Sarcophagid larvae preying upon the others, or they may 

 be more successful in the struggle for food; at least they have the 

 advantage of being deposited as larvae. I w^ould not care to suggest 

 that this relationship would hold farther south where there are more 

 oviparous forms which breed in excreta. As Sarcophagids are less 

 numerous and less commonly found in houses than oviparous species 

 that frequent excreta, they may perhaps be considered beneficial 

 in so far as the relationship suggested above holds good. In one 

 experiment, 970 Sarcophagids were reared from a single stool which 

 was found in a back alley and had been exposed one day; 944 of these 

 were Ravinia peniculata R. Pkr. Sarcophaga tuberosa sarracenice 

 (Riley) was bred from fish, but was not found in excreta though 

 supposed to frequent it abundantly. S. cooleyi R. Pkr. was bred in 

 large numbers from fish, and also from the carcass of a kitten. 



The species of Ravinia are probably primarily breeders in excre- 

 mentous substances, and when excreta is deposited in the open are 

 commonly the first flies to be found on it. Ravinia communis R. Pkr. 

 was bred from human excrement, cow dung, horse manure, hen manure 

 and pig manure; R. peniculata R. Pkr. from human excrement and cow 

 and pig manure; several other species, some undescribed, are also 

 known to breed in manures of various kinds. There are very few 

 records of these species under other conditions, I also have records 

 of excreta-frequenting habits for several undescribed species of Sarco- 

 phaga. These flies also frequent garbage to some extent as it is found 

 exposed in the vicinity of stores and residences. 



President H. T. Fernald: I suppose all economic entomologists 

 fully appreciate the necessary foundation of systematic work upon 

 which their studies must rest. It has been of interest to me in exam- 

 ining collections throughout the country, as I have had the oppor- 

 tunity, to note the number of Sarcophagidse labeled Sarcophaga sp.'' 



I think we are to be congratulated on the fact that since Mr. Aldrich, 

 Mr. Parker and others have been doing so much work along this line, 

 this unsatisfactory condition promises shortly to be removed and 

 that economic studies of the Sarcophagidse may apply to the 

 particular species concerned in each case. 



President H. T. Fernald: The next paper on the program will 

 be by Mr. J. W. McColloch. 



