PROCEEDINGS OF THIRTY-SIXTH FRUIT-GROWERS ' CONVENTION. 163 



twenty-four hours, and the newly hatched larvae begin feeding at once. 

 To gain an estimate of the number of larvae developing in an average 

 horse manure pile five samples were taken from various parts of the 

 pile and the larva? counted, the weight of the samples being previously 

 taken. The total weight of the samples was fifteen pounds and the 

 total number of larvae (maggots) was 10.282. all of which were quite 

 or nearly full grown. This gives an average of 685 larvae per pound, 

 and the entire pile was estimated at not less than 1.000 pounds, of 

 which certainly two thirds was infested like the samples. A little 

 arithmetic gives us the astonishing estimate of 455,525 maggots in an 

 average manure pile of only four days' standing. This particular 

 manure pile (not from a livery stable, either) was only one of many 

 known to exist in various parts of the city. No wonder flies fairly 

 swarm in the vicinity of these choice ornaments ! 



The growing or larval stage requires from four to six days, after 

 which the maggots often crawl away from their breeding place, many 

 of them burrowing into the loose ground just underneath the manure 

 pile, or crawling under boards or stones, or into dry manure collected 

 under platforms and the like. The maggots often pass three or four 

 days in this condition before they change into pupae (the resting stage), 

 recognized as small chestnut colored barrel-shaped objects in which 

 the maggots transform to the winged fly. This resting stage requires 

 from five to ten days and more, varying according to temperature ; thus 

 the time necessary for a fly to develop from an egg to the winged insect, 

 as we know it. is usually from twelve to fourteen days in midsummer. 



We are now familiar with the facts of development and habit and 

 have this knowledge as a basis for action against the pestiferous and 

 dangerous fly. 



ESSENTIALS OF HOUSE FLY CONTROL. 



Methods of control are planned along the lines suggested by the 

 study of the life history and habits of the insect. The more familiar 

 we are with these two factors, the better able are we to attack the 

 problems of control. Usually the most vulnerable stage in the life his- 

 tory is selected at which time the insecticide may act most speedily, or 

 during which time permanent preventive measures are most effectively 

 applied. Certainly wherever the breeding places can be eliminated, 

 this method should be followed. It has been already pointed out that 

 at least ninety-five per cent of our city house flies have their origin in 

 the open horse manure pile, and that the remainder are bred in the 

 open garbage can and similar situations. The point of attack is clearly 

 shown. The open manure pile must be abolished and stables must be 

 ~kept clean. Receptacles containing kitchen refuse must be kept tightly 

 closed or screened and refuse of any kind must not be thrown out into 

 the backyard to decay. The reason for this cleanliness in human habits 

 is to prevent the female house fly from depositing her eggs upon the 

 material which is to provide food for the maggots. 



Permanent preventive measures will always be far less expensive in 

 the end, and also very much more effective than the application of 

 temporary methods in the form of insecticides, which must be applied 

 over and over again with continuous expenditure of time, labor, and 

 money. 



