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less frequently found. Contrary to the opinion that locust outbreaks 

 in Ital}^ last two or three years and then disappear of their own accord, 

 these locusts may continue to multiply for many years without difficulty 

 and their almost total disappearance, if not due to the action of man, 

 cannot occur except through that of Empusa {Entomophthora) grylli, 

 which is much less frequent, if not very rare, in the southern provinces. 

 Not one case of mycosis was found during three successive campaigns 

 against locusts in Sicily. If the system of using arsenites of soda and 

 lead to poison the grass be set aside on the score of danger, the only 

 remaining efficient means of controlhng locusts are : (1) The use of 

 flames of burning petroleum mixed with benzine ; (2) spraying the 

 locusts with contact washes ; (3) capturing them with sheets and 

 collectors ; (4) collection and destruction of the egg-masses. The 

 petroleum flame should always be adopted where petroleum is cheap, 

 or where the infestations are numerous, severe and threatening in the 

 vicinity of sown fields, or where it is not possible to have sufficient 

 C[uantities of insecticide washes at hand. A number of sprayers 

 suitable for flame work are described. Almost any nozzle is good 

 which produces a large mist of fine petroleum spray. The addition 

 of 10 per cent, of benzine makes perfect combustion easy. The men 

 must be quick and intelligent and must work with the wind behind 

 them if accidents are to be avoided. The costhness of this method in 

 Italy (the mixture costs about Is. lOd. a gallon) prompted practical 

 experiments in the comparison of the efficiency and relative cost of 

 various insecticides to be carried out in April 1914. Of the liquids 

 tried, an emulsion of tar-oil-soap yielded the best technical and 

 economical results and is the one described here. It kills the grasses, 

 but the meagre pasture would have met with the same fate from the 

 locusts and a portion was sacrificed in order to save the sown crops. 

 To prepare this emulsion in the field, the author used cylindrical sheet- 

 iron boilers, 26 inches high and 22 inches in diameter and fitted with 

 handles. Into each, 14| gals, of water was poured and the boiler was 

 put on a fire ; when the water was warm, 131- lb. of yellow emulsive 

 potash soap was added and well mixed wdth a stick. When the soap 

 and water began to boil, 6f gals, of heavy tar-oil was added, a little at 

 a time, with continuous stirring and allowed to boil for about 10 

 minutes. The emulsion was then poured into an open cask ; it 

 contains 30 per cent, of heavy tar-oil and 6 per cent, of soft soap. 

 If fuel costs as much as Is. 6d. per cwt., a certain saving can be effected 

 by boiling 22 gals, of water with 20 lb. of soft soap and then pouring 

 the liquid into a vat containing 100 lb. of heavy tar-oil and stirring 

 until a uniform mixture is obtained. This emulsion does not keep so 

 well as the boiled one, but is equally efficient if used on the same or 

 the next day. In exceptional cases, the emulsion can be prepared 

 without heat, but does not seem to be so effective or so stable. With 

 the idea of retarding the evaporation of the emulsion sprayed on the 

 locusts — exposed to the burning sun and wind — the author added 

 1 or 2 per cent, of common salt to the emulsion and found that its 

 action was thereby increased. For use, the concentrated emulsion 

 was diluted as follows : To each petroleum tin (a convenient unit for 

 field w^ork) of emulsion, 5 of water were added when the locusts were in 

 the first larval stage, 4 when they were somewhat larger, 3 when they 

 reached the nymph stage, 2 when their wings began to appear and 1|- 



