July, 1914] THE APPLE MAGGOT, 67 



ATTRACTION TO BAITS, AND FEEDING. 



Many observations, together with the results of experiments 

 described in paragraphs that follow, as well as the results of 

 extended trials of poison bait sprays and of poison trap pans, 

 lead to the conclusion that the adult flies of this species are not 

 noticeably attracted to any one of a variety of substances that or- 

 dinarily prove strongly attractive to many other insects. 



The substances tried included, among others, sugar, glucose 

 and molasses, which serve as a compelHng lure for other species, 

 such as the housefly. In no case did such baits prove notably 

 attractive. 



Observations of feeding habits in the open, under normal con- 

 ditions, were as follows: 



When a fly is resting on an apple it has been observed to extend 

 its proboscis and touch the surface of the fruit. Probably this 

 is for feeding on such substances, found on the skin of the apple, 

 as can be taken up by the mouth parts, although there is no 

 definite proof that this is the case. If an apple is cut, so as to 

 expose fresh pulp, flies seem moderately attracted to it. 



Flies noted in other parts of trees, especially when resting on 

 leaves, were not observed to give any indication of feeding. 



The impression of the writer, and of others connected with the 

 work of this investigation, is that in general the flies feed rather 

 sparingly, so far at least as daylight hours are concerned. 



Experiments in 1909. At the beginning of the investigation 

 in 1909 an apparatus was arranged by which it was hoped to 

 secure data on the reaction of the flies to substances that might 

 be used as baits. 



This device consisted of two glass bell-jars, the bottoms of 

 which were fastened together. One bell-jar was covered with 

 black paper and was directed away from the light. In the farther 

 end of this was fitted a glass cylinder. The substances to be 

 tested were placed in this cylinder. Later the device was 

 modified by arranging the two bell-jars as before with bottoms 

 fastened together, but with both jars uncovered. The two 

 were placed parallel to the source of light. In the end of one 

 jar was fitted a glass cylinder containing distilled water; in the 

 end of the other was the substance being tested. 



Ten flies were used in the tests with the first apparatus. The 

 substances tried and the results recorded were as follows: 



