109 



against pests of field crops, especially against locusts, is laborious and 

 inconvenient. Sodium arsenite is considered to be the most convenient 

 and effective remedy against various locusts such as Locusta viigratoria, 

 Calliptamus italicus, Dociostaurus maroccanus and Gomphocerus sibiri- 

 cus, which perish from this insecticide in from 15 to 20 hours after 

 spraying, i.e., quicker than when Paris green and lime is used. 



It has not yet been tried in orchards, but is expected to prove 

 successful. Djipsin is very effective against orchard pests, but 

 less so against locusts and pests of field crops. Barium chloride is 

 successfully used against Hyponomeuta malinellus and Bothynoderes 

 {Cleonus) punctiventris. 



During the discussion on this paper, it was pointed out by K. K. 

 Miller and G. S. Sudeikin that good results were obtained at Kishinev 

 and Voronezh with London purple. In the former place, it was 

 used in a liquid form and no scorching was observed even with a 

 strong concentration ; in the latter, it was applied in the form of 

 powder (1 lb. of purple mixed with 10 lb. of flour) and gave good 

 results against caterpillars of Pieris rapae, Plutella maculipennis 

 icriiciferarum), and Barathra (Mamestra) brassicae, while a solution 

 proved less effective. 



ScHREiNER (J. Th.). PeaynbiaTbi npMMtHeHifl Hoearo MHceKTMCMAa, 

 xpOMOBO-KMCnaro CBMHUa. [The results of the appUcation of a 

 new insecticide, acid chromate of lead.] pp. 50-52. 



Experiments with acid chromate of lead in the government of 

 Petrograd are described. In order to prepare this insecticide, potassium 

 bichromate, one part by weight, and lead acetate two parts, were 

 dissolved separately and by mixing the two solutions together, acid 

 chromate of lead was obtained in the form of an amorphous floccular 

 precipitate. This insecticide was tested in various strengths, from 

 5 oz. to 10 oz. in 27 gallons of water, upon caterpillars of Pieris brassicae 

 and rapae, upon the larvae of Nematus septentrionalis, and on the adults 

 of the beetle, Agelastica alni. The insecticide was retained satisfactorily 

 on the foliage of apples, birches and alders, but on cabbages, it was 

 necessary to add molasses. No damage to the trees was observed, 

 but the insecticide proved very slow in its effect and though the insects 

 ceased to feed on the sprayed plants, the death-rate was very low. 

 It is considered remarkable that an insecticide consisting of two 

 poisonous substances should prove so harmless to insect pests and 

 the necessity for further experiments with this substance is indicated. 



During the discussion, Prof. E. M. Vassihev stated that his experi- 

 ments with this insecticide showed that it does not adhere satisfactorily 

 to foliage and that it had had no effect on Athalia spinarum. I. V. 

 Emelianov referred to the good results obtained by this preparation 

 in India by Lefroy and others. 



UvARov (B. p.). BnMwaMiijifl nepcneKTMBbi btj lexHMKt 6opb6bi ci, 

 capaHSeBblMM. [The immediate prospects in the technique of the 

 fight against locusts.] pp. 53-60. 



With regard to this paper [see this Review, Ser. A, iii, pp. 98-99] it 

 was pointed out at the Conference by Th. N. Lebedev that sodium 



