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JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 8 



several Lepidopterous larvae, several adult beetles, several grass hop- 

 pers and a Mantis, and according to one record from cow manure, 

 though I am skeptical about this. Sarracenice without doubt breeds 

 at times in dead fish and is at other times a parasite of insects; it has 

 even been recorded from human excrement, but this might have been 

 a misidentification. 



We seem to be deahng with a group in which the parasitic habit is 

 just being formed, and is still much more plastic than is the case with 

 Tachinidse, connecting the latter with the true Muscids — just where, 

 by good luck, we happen to have placed them in our lists. 



Mr. R. R. Parker: I would like to add a few words to what Dr. 

 Aldrich has said, and shall deal mainly with their excreta-frequenting 

 habits. My data are based principally on personal observations 

 made during the past summer while carrying on investigations for 

 the Montana State Board of Entomology, undertaken in part to 

 determine what Montana flies may be considered of actual or potential 

 importance as disease agents or as carriers of disease. 



In one experiment in which a trap was attached to the back of a 

 privy with a sunken vault so as to catch the flies which had visited 

 the excreta, 43 Sarcophagids were captured in one month, about 

 0.5 per cent of the total catch, and these were principally Sarcophaga 

 cooleyi R. Pkr., a species not known to breed in excreta. 



Of flies captured with excreta as bait, Sarcophagids constituted 

 8.75 per cent of the catch in seven experiments. Of these, Ravinia 

 communis R. Pkr. was the most numerous and specimens of R. penicu- 

 lata R. Pkr., Sarcophaga Immorrhoidalis Meig. and S. cooleyi R. Pkr. 

 were also taken. All were females except a few specimens of S. 

 hcemorrhoidalis. It is interesting to note that the great majority of 

 oviparous species were also females. 



Of flies noted in houses no proportionate record was kept, but 

 specimens of Ravinia communis R. Pkr., R. peniculata R. Pkr., Sarco- 

 phaga hcemorrhoidalis Meig. and S. cooleyi R. Pkr. were either captured 

 or observed, though only occasionally. Under certain conditions, 

 such as those prevailing in construction camps, it is probable that a 

 larger proportion of these flies would be found frequenting food, than 

 under town or city conditions. 



The most interesting results were obtained from breeding experi- 

 ments. From material taken from privies with sunken vaults no 

 Sarcophagids were reared, but only oviparous species, mainly Ophyra 

 leucostoma Weid., and species of Fannia, Limosina and Scatopse. 

 On the other hand, when dealing with material exposed in the open, 



