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very feeble, aud it is in all probability in this stage that they 

 liibernate. The pnpa stage lasts from 11 to 16 days, so that 

 the total diiration of the three stages works out at about 3 months. 

 This corresponds with the incidence of flies in nature. They 

 appear and increase rapidly in numbers from the end of May and 

 throughout June, these indiyiduals being probably from last 

 year's larvae; they diminish during July and the beginning of 

 August, and again become numerous from the latter half of 

 August until November, when they disappear. 



Habits of the Flies.- — On warm still sirocco nights from June 

 to October flies are to be found. They appear at sunset, and if 

 the wind has kept them in their breeding haunts for a day or 

 more their biting is very noticeable. When the wind blows at 

 night they do not appear until it drops and disappear at day- 

 break, and if a wall be then watched they may be seen entering 

 it. Wind seems to be very objectionable to them, for, even in a 

 cage, if exposed to a breeze they cling to the chiffon covering and 

 their wings become twisted. They do not like daylight and 

 direct sunlight appears to be injurious to them. They are 

 attracted by artificial light, if not too bright ; thus they will not 

 fly to electric light, but it has been noticed that if a piece of white 

 paper be put beneath the oil lamps used in barracks it is soon 

 covered with the bodies of the flies which have been burnt during 

 the course of the evening. 



Distance of Flight. — This is a very difficult question to settle, 

 but certain observations have been made which throw some light 

 upon it. Tort Chambray has its barrack block placed on a 

 plateau well exposed to the wind and 40 to 50 yards from the 

 nearest fortification walls. Here the men do not suffer from the 

 bites of sand-flies. The married quarters, which are close to the 

 bastion wall, at a distance of 15 to 20 yards, were infested with 

 flies. It would thus appear that the range of flight is something- 

 less than that of the mosqiiito ; the height of flight cannot be 

 accurately determined, but there is no doubt that, except where 

 the building is on a bastion or where there are rubble walls erected 

 against the building, the upper floors are much freer from the 

 fly than the lower. 



Food. — Both male and female flies have a habit of burying their 

 mouth-parts in moist organic detritus. The females alone are 

 blood-suckers and no male fly has been found to contain blood. 

 The females will suck blood from any warm-blooded animal, 

 and have been caught issuing from a wall with fresh blood in 

 the stomach, probably from biting a rat. 



Prophylactic Measures. — It was suggested in 1910, that if all 

 walls in close proximity to barrack rooms were properly faced 

 so as to prevent communication with the interior, the number of 

 flies would be lessened. This was done on an experimental scale 

 in the Eloriana Barracks which have always been notorious for 

 cases of sand-fly fever. About 60 yards of the wall was cleared 

 of vegetation and all cracks and holes were filled in, and, 

 apparently as a result, in the early part of the season the barracks 

 were remarkably free from sand-flies, though later they made 

 their appearance. It seems to be necessarj', in order to keep 



