169 



about the middle of November. They Ccaii still be found in their 

 breeding haunts in small numbers during December. The latest date 

 on which a fly was seen was 14th January ; this was in a breeding 

 ground where the temperature kept up to 70° F. till January ; on the 

 temperature falling to 60° F., no flies were seen. There is thus an 

 interval of about four months during which the adult fly is not to be 

 found. The winter is passed in the larval stage. It has been found 

 experimentally that dryness of the surroundings prolongs the length 

 of the various stages, and under such conditions the complete cycle 

 takes as much as four to five months, while when warmth and moisture 

 are present, the shortest time has been found to be thirty- four days. 

 The larva is motile and eats voraciously ; when mature, its total 

 length is about 5 mm. ; it then becomes motionless, empties its intestinal 

 canal, and curves its head over till it touches the abdominal surface ; 

 when about to pupate, it comes up to the surface of the detritus, 

 unless it is dry. Bred flies usually feed before pairing, the females 

 alone sucking i3lood. When pregnancy is short (seven days), the eggs 

 are more likely to be fertile, and when this is the case, they arc all laid 

 within twenty-four hours. On warm nights the flies appear just 

 before sunset; they are attracted to inhabited dwellings and bite 

 both warm and cold-blooded animals. At sunrise they disappear, 

 either to their breeding haunts, or to dark corners of rooms. They 

 dislike sunlight, but are attracted by artificial light, and are to be 

 found in considerable numbers on and around paraffin lamps. It 

 seems probable that examples of P. papatasii, which were bred in a^ 

 certain cave, were present in dwellings within fifty yards of it, but 

 only rarely beyond this limit. They do not fly high, and the top 

 rooms of houses which are not shut in by high walls are comparatively 

 free from them. Sandflies are attacked by an ectoparasitic mite, 

 which hatches in woodlouse excreta, and is to be found attached to the 

 thorax of the fly ; it apparently is not a true parasite, as it occurs 

 when no flies are present and does not injure the larval stage. On 

 the other hand a minute pseudoscorpion attacks the larvae. A fungus, 

 pathogenic to the fly, has been provisionally named Empiisa papatasii. 

 A fly thus infected is recognised by the fact that ingested blood appears 

 to remain in the thorax, causing it to appear nearly as red as the 

 abdomen. On dissection of such a fly motile spores may be found in 

 the salivary glands, whilst the mycelial form is seen in the intestines. 



La destruction des mouches ; rassainissement des cantonnements et des 

 champs de bataille. [The destruction of flies and the cleansing of 

 cantonments and battle-fields.] — La Vie Agric. et Rurale, Paris, 

 V, no. 10, 31st July 1915, p. 181. 



If used too freely on manures, heavy coal oils and 5 per cent, solutions 

 of cresyl may, in certain cases, injure the value of them, while heavy 

 tar oil sinks to the bottom in water. These disadvantages do not attach 

 to the residual oils of tar, that is to say, the oils deprived of their 

 naphthaline content and dephenolised. Such oil, with the addition 

 of resinate of soda, may be mixed with water in the proportion of 

 2i per cent, to form a stable emulsion, which may be spread in a thin 

 film over extended surfaces of decomposing matter. The pecuhar 



(C209) » 



