268 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 3 



of arseiiite of soda in 8 gallons of water. Its effectiveness lies in 

 the sugar or molasses of which locusts are very fond, and to which they 

 are attracted long distances by the odor. It is therefore best to use 

 as crude and strong smelling a substance for sweetening as can be pro- 

 cured. At first white arsenic was employed, as a poison, which had 

 to first be boiled with caustic soda to produce a soluble compound. 

 The late Mr. Simpson improved this by introducing the use of arsenite 

 of soda which is soluble in cold water. The latest improvement is the 

 production of a concentrated stock solution of arsenic and sugar. Such 

 a compound has been made, at the writer's suggestion, by the Atlas 

 Preservative Co., of England and is known as Atlas Locusticide. It 

 is put up in 1 gallon and 5 gallon tins and only needs to be mixed 

 with the proper quantity of w^ater before using. Locusticide has 

 helped very much to push the work in the coastal regions such as 

 Mocambique where transport is difficult and costly and where incom- 

 petent persons often have to prepare and handle the spray. In Cape 

 Colony they prefer to prepare their own concentrated solution from 

 arsenite of soda and molasses ; but in other parts the cost of tins and 

 the skilled labor necessary make such a method impossible. 



The method of applying the spray is to locate a swarm of hoppers 

 and note the direction in which they are moving. Then late in the 

 afternoon or early in the morning spray a strip of grass varying in 

 width from 20 feet to wider, depending on the size of the swarm, 

 clear across the front. If it is a small swarm spray a ring completely 

 around them. During the night the hoppers bunch up together on the 

 grass or bush to sleep, and in the morning as soon as the sun has dried 

 off the dew they begin to eat and move outward. Consequently if a 

 choice bit of grass has been sprayed, this is what they will attack 

 first. They will die in from one or two to 24 hours, depending on the 

 strength of the solution used. So fond are they of the sugar that if 

 not enough sprayed grass is left for all the hoppers the last comers 

 will devour the first which have died or are dying and so one dose of 

 poison may often kill 3 or 4 hoppers. 



The writer once visited a small town in the north Transvaal which 

 was being overwhelmed with locusts. The locust officer had just 

 sprayed a strip of grass about 10 or 15 yards wide clear across one 

 side of the town lands or commonage to cut off an approaching swarm 

 of hoppers. This sw^arm was at least 5 miles across the front. On 

 they came till they struck the sprayed grass where they staid awhile 

 and fed. The spray had purposely been made weak to avoid the 

 danger of poisoning cattle and the hoppers had taken some time to die. 

 But when we arrived every fence corner and every corner of a house 



