BENZENE. 335 



properties it does not replace carbon disulphide, except in isolated 

 cases, and it can never render the same services as the latter. Its 

 preponderating advantage over carbon disulphide is that it has a more 

 prolonged action, especially in warm, dry weather. Benzene is also 

 used in emulsions against aerial parasites, either pure or mixed with 

 other insecticides. Debray records the good effect of an emulsion con- 

 sisting of benzene 2 lb., ordinary alcohol ^ lb., soft soap 3 lb., in 10 

 gallons of water ; and a solution of naphthalene in 8 parts of benzene. 



Melolontha vulgaris, L, (cockchafer). — The benzene from gas- 

 works destroys the white-worm. Mohr advised its use as far back 

 as 1893. Eitzema Bos records the good results obtained by treating 

 fields in Holland, Taschenberg those obtained in the neighbourhood 

 of Trieste, and Croisette-Desnoyers in pine plantations. Injections 

 of benzene into the soil are made by the pal injector, like those of 

 carl)on disulphide. The nature of the soil, as well as the season, 

 decides the number of holes and their depth. Thus holes are made of 

 8-10 inches intervals in light soil and 6-8 inches in heavy soils ; the 

 larvae of the cockchafer hving, according to the season, at different 

 depths, the depth of the holes with the pal must be varied with the 

 position occupied in the soil by the white-worm. The depth varies 

 from 12-28 inches. The precautions to take are described under 

 car bo a disulphide. The amount of benzene to use per hole is 5 cubic 

 centimetres. Fields of lupines only receive one injection per square 

 metre. In pine plantations Croisette recommends to make injections 

 every 70 centimetres (say 28 inches), and two to three injections a year. 

 The results obtained in young plantations which suffer much from white- 

 worm are perfect, and the treatment in no way injures the trees. Ben- 

 zene has often given favourable results where carbon disulphide has 

 failed. These doses sufficient to overcome the lamellicorns never 

 injure the plant. 



Cetonia stictica. — Eitzema Bos and G. Staes advise to destroy it 

 to inject 5 cubic centimetres into dunghills every 8 inches by the pal 

 injector. The benzene destroys the larvae. 



Elaterides (wire-worms). — Eitzema Bos found that wire-worms, 

 the larvae of the elaterides, resist benzene injections. 



Othiorhynchics sidcatus (vine weevil). — Benzine has been recom- 

 mended by Mohr in sprayings round the stocks with the view of 

 destroying the larvae of this weevil. Eitzema Bos regards it as inert 

 in this instance. 



Ceutorhynchus sulcicollus (cabbage weevil). — Mohr advises to com- 

 bat it with benzene. As soon as the plants have five leaves, holes are 

 made 8 inches around the plant, 8-12 inches in depth, and 5 cubic 

 centimetres of benzene run into them and the holes closed up forthwith. 

 The adult insect, may also be exterminated by spraying with a soapy 

 water emulsion of benzine. 



Molytes coronatus (carrot weevil). — To destroy larvae which attack 

 fleshy part of carrot, Mohr makes round holes round young carrot 4 

 inches deep, into which he pours 5 c.c. of benzol and fills up at once. 



Saperda carcharias, L. (Saperde chacjrince). — ^To destroy the cater- 

 pillars in their burrows, chloroform, turps, and benzene are used. 

 Benzene is preferable. De la Blanchere operates thus : By means 



