REPORT OF THE STATE ENTOMOLOGIST I909 1 3 



Co. of Grand Rapids, ]\Iich., with the preparation so famihar on 

 tanglefoot fly paper, were tacked up at stations 2, 4, 6, 12, 14, 18 

 and 22 about 5 feet from the ground. The vivarium was located 

 about 20 feet from one barn where a horse was kept, the manure 

 from the animal being thrown outdoors. There was another barn 

 where at least two animals were kept throughout the summer about 

 40 feet away to the southwest and another barn about 50 feet due 

 east. This latter had been occupied in previous years by six to 

 eight horses, and when the vivarium was constructed it was ex- 

 pected that an equal number of animals would be kept in the build- 

 ing throughout the summer. Owing to a change of plans but one 

 horse was kept in this barn, and as a partial result of this change 

 there have been considerably fewer flies than in pre\4ous years. 

 Furthermore, the excessively cool wxather continuing well into June 

 greatly delayed the appearance of the house fly in numbers. Rela- 

 tively cool weather continuing throughout the summer has also 

 served to prevent rapid breeding. This combination of causes has 

 resulted in house flies being much scarcer than usual. 



Experiments. House flies w^ere becoming somewhat abundant 

 June 23d and operations were commenced by placing mackerel kits 

 nearly filled with sterilized horse manure at stations \_see numbers 

 on plate] 6, 12, 18 and 23. At the latter station there was a second 

 mackerel kit or check pail containing ordinary horse manure. 

 Practically no flies were observed about the vivarium June 23d and 

 the same was true the morning of the 24th. An examination Sat- 

 urday afternoon the 26th gave negative results, since there were no 

 evidences of flies in the house, aside from a possible specimen or 

 two just within the screen door. On the afternoon of June 29 a 

 fly was seen at station 22 and several at station 6. There were no 

 signs of horse flies at stations 8, 18 or 12. July 17, 5 or 6 house 

 flies were seen about the door. August 3 they were rather numer- 

 ous in and about the vivarium. On this date a second pail of 

 sterilized horse manure was placed at each of the stations just men- 

 tioned and in addition, a pail about % full of miscellaneous swill 

 covered with 2 inches of horse manure was set just outside the 

 door in the hopes of attracting more flies. The records will now 

 be given by stations, beginning with the pail outdoors. 



Pail outdoors containing swill and manure. August 22^ this pail 

 was found to be filled by recent rains and contained several ^luscid 

 larvae. September nth this pail, though well shaded by squash 

 vine leaves, contained 12 large dipterous larvae, probably M u s c a 

 domestica and a rat-tail syrphid larva, probably E r i s t a 1 i s 

 t e n a X Linn. We were unable to rear these larvae to maturity. 



