nOUSE-FLY INVESTIGATIONS. 



487 



of flies came to these peptone baits, but not in very lai^ge numbers, 

 i. 6., a certain number of Calliphora, Lucilia, and Fannia^ a few 

 Musca and Sarco-phaga^ as well as many Pioj^hila. 



The blow-flies weie always more attracted by meaty substances, 

 although quite a number of them have been caught when mix- 

 tures of peptone were the only baits exposed. 



Some of the different organs, as well as oi"dinary meat (muscle), 

 and also dead birds, fish, etc., were used as baits. Of these, 

 liver, brain, and fish were the most attractive, remaining so for 

 a considerable time. Blow-flies very soon came to feed on these 

 when exposed in sunny places, so that they became blown very 

 quickly. When the digestive action of the maggots had had 

 time to act upon the baits, they were extremely attractive, but 

 gave ofl:' a most offensive smell. Since liver, brain, and fish were 

 the most attractive of the meaty substances, they were tested 

 against each other, in order to find out their relative attractive- 

 ness. First, the attractiveness of each for blow-flies was tested 

 separately, when the mouths of two of the jars were closed by 

 being covei'ed by glass plates. Later, two at a time were left 

 open, and finally all the three were left open together. Liver 

 was then found to be by far the most attractive, although 

 when fish and brain were exposed alone, they each caught a 

 considerable number of flies. 



Details and results are given below in Table I. 



Table I. 



Comparison of the Attractiveness for Blow-flies of liver, 

 brain, wad fish. 



