80 Observations on the Ilal^its of Certain Flies 



No. 6 in experiment 2, treated with borax and creosote oil mixture 

 gave still lower mean temperature. 



4. Owing to possible uneven sampling of the manure in the first 

 experiment and lateness of the season of the second, the minimum 

 effective quantity of creosote oil mixture was not determined. But it 

 should be noted that it seemed doubtful whether I gallon to 1 ton of 

 manure would prove sufficient, whilst 4 gallons did prove efEective. 



5. Incremental treatment is superior to surface treatment. 



6. Though the 6 tubs in experiment 2 were under observation until 

 spring 1917 no M. domeslica emerged from any of them after the winter. 



Experiment to attempt to determine (1) the depth at which it is 

 necessary to bury material infested with fly larvae, in 

 different soils, to prevent the escape of the adult, (2) the 

 effect of filling in the pits loosely or of ramming the soil; 

 and (3) the distance through which the adult flies are able 

 to climb when emerging from pupae in different soils, 

 loosely or tightly packed. 



In the Military Manual of Elementary Hygiene, 1912, two methods 

 are given by which to dispose of excreta: (1) In the "Long and deep 

 trench system" a trench 5 yards long x 16 inches wide x 3 feet deep 

 is the allowance for 100 men; and "the contents of latrine trenches 

 should be covered with a couple of inches of dry earth daily." (2) In 

 the "Short and shallow system" the trench is made 1 foot deep and 

 lasts 1 day, unless the contents is levelled down and the covering of 

 earth is finely broken down, when it may be made to last longer." 

 In paragraph 13, page 65, one is told that "so soon as the latrine- 

 trenches have been filled in to within six inches of the ground level 

 their use should be discontinued, earth thrown in, and turf or sods 

 replaced." 



As regards refuse it states that in bivouacs and camps of a temporary 

 nature these receptacles (for disposal of refuse) may take the form of 

 pits or holes, but where these arc employed, the contents must be 

 covered over with at least six inches of earth two or three times a day 

 to prevent flies being attracted to them. 



No instructions to vary the depth according to the nature of the soil 

 are given. A couple of inches of dry earth thrown over the excrement 

 would probably be insufficient to prevent the material becoming infested 

 with flies' eggs; and six inches has been proved too little to prevent the 

 escape of any flies developing (see Uraham-Smith, 1916, p. 503). 



