ENTOMOLOGY. 597 



Canadian government officials at the risk of the shijijjers or consignees. A list of 

 plants exempt from fumigation is also given. 



The use of hydrocyanic-acid gas in the control of insects, H. Faes {Bui. Soc. 

 Vaud. Sci. Nat., 4. ser., 39 {1903), No. 146, jip. 65-6";?).— Attention is called to the 

 disadvantages in the use of carbon bisulphid as compared to hydrocyanic-acid gas. 



A number of experiments were made by the author in fumigating greenhouses 

 which contained a large variety of plants of different hardiness, infested with scale 

 insects and plant lice. The amount of cyanid of potash used per cubic meter of 

 spa(!e varied from 2 to 5.25 gm., while the sulphuric acid and water were used at the 

 rate of 4.5 cc. and 6.75 cc, respectively, for each 3 gm. of cyanid. The period of 

 fumigation varied from 25 to 35 minutes. It was found on ventilating the greenhouse 

 after fumigation that the gas had entirely disappeared within 15 minutes. 



A list is given of the plants in the various greenhouses in which experiments were 

 made. The insects which it was specially desired to kill were Dactylopius adonidum 

 and Aphis dianthi. When cyanid was used at the rate of 3.5 gm. per cubic meter 

 and the greenhouse was fumigated for 30 minutes, all species of scale insects, includ- 

 ing the one just mentioned, were killed. Equally satisfactory results were obtained 

 in the destruction of plant lice. 



Observations were also made to determine the effect of the gas upon other ani- 

 mals. When the cyanid was used at the rate of 3.5 gm. per cubic meter, white 

 mice and guinea pigs were killed within 5 minutes, and cats succumbed after 15 

 minutes. Frogs and salamanders were destroyed during a fumigation period of ordi- 

 nary length. No injury was done to plants except when a large quantity of cyanid 

 was used. The author considers that 5.3 gm. per cubic meter is too much and 

 recommends for the fumigation of greenhouses a charge of 4.25 gm. per cubic meter. 



Insecticides, C. L. Penny {DeUmare Sta. Rpt. 1902, pp. ^4-87). — An analysis of 

 a samijle of arsenite of lime as prejiared by a fruit grower showed that only 6.77 per 

 cent of arsenious acid was present and that probably some of the acid was lost in 

 boiling. The addition of sodium arsenite to Bordeaux mixture at the rate of 2 oz. 

 per barrel was found to leave about 2.75 per cent of the total arsenious acid in solu- 

 tion. This quantity, however, is considered harmless in Bordeaux mixture. 



When Paris green, Bordeaux mixture, and crude petroleum were shaken together 

 it was found that after being allowed to stand for some time a greenish blue scum 

 formed on the surface, consisting of petroleum, while a clear middle layer consisting 

 of the clear portion of the Bordeaux mixture was formed, and a blue precipitate, 

 consisting of the sedimentary portion of the Bordeaux mixture and Paris green, 

 collected at the bottom. In mixing whale-oil soap, Paris green, and Bordeaux mix- 

 ture it was found that the clear solution of soap was completely precipitated by the 

 Bordeaux mixture, and that an insoluble lime soap was thus formed. Neither cop- 

 per hydroxid nor Paris green was found to have any perceptible chemical effect on 

 whale-oil soap when the latter was mixed and agitated with either of the former. 



Remedies for insect and fung-us pests of the orchard and farm, A. M. 

 Lea {Tasmania: Dept. Agr., 1903, ;?. ed., pj). 53, figs. 30). — This is an enlarged and 

 revised form of the original edition (E. S. R., 14, pp. 466, 467). 



A monograph of the Culicideo or mosquitoes, F. V. Theobald {London: 

 British 31us. Nat. Hist., 1903, vol. 3, pp. XVI-i'359, jils. 17, figs. 193).— This is a con- 

 tinuation of the author's monograph on mosquitoes (E. S. E., 13, p. 770), and was 

 issued for the purpose of including descriptions of new species and other interesting 

 material which has been examined since the publication of the 2 previous volumes. 

 More than 100 additional collections have been received and from these collections 

 88 new species and 8 new varieties have been found and described. Notes are given 

 on the biology and life history of the more important species. 



Soil nitrification v. the incidence of malaria and other mosquito-borne 

 diseases, A. E. Waddell {Lancet [Londonl, 1903, J, Nu. 23, p>p. 15S9-1590; abs. in 



