286 



sligMly soluble in water, and wlien mixed with air extremely irritating 

 to the eyes and respiratory organs. When very largely diluted 

 with air it has merely a slightly aromatic and bitter smell. Caution 

 is necessary in its use, but it is less dangerous than hydrocyanic acid 

 gas, which it is possible that it may replace. It is prepared by the 

 action of picric acid on calcium chloride. 



In testing its value as an insecticide, a weighed quantity was intro- 

 duced into a 1 or 2 litre wide-necked flask by means of a capillary 

 pipette delivery in small drops, the flask being then corked and 

 thoroughly shaken to ensure the even distribution of the vapour 

 through the contained air. After a quarter of an hour, the insects 

 to be tested, enclosed in a piece of gauze, were lowered into the middle 

 of the flask, by means of a thread the other end of which was held 

 between the neck and the cork. After a certain exposure, the insects 

 were withdrawn, and, if not dead, were kept under observation upon 

 the foliage of their usual food-plant. In tests with Aphids, a piece 

 of a twig of the food-plant bearing the insects was placed in a tiny 

 flask containing water and the whole was lowered by a thread into the 

 flask. 



The insects experimented with included the larvae of such Lepidop- 

 tera as Sparganothis fillefriana and Polychrosis botrana, sawfly larvae and 

 Aphids. The results showed that exposure for from 5-10 minutes 

 in an atmosphere containiug 1 to 2 centigrammes of chlorpicrin to the 

 litre was sufficient to kill insect larvae and Aphids either immediately 

 or in the course of a few hours. Larvae exposed to a concentration 

 of half this strength ceased to feed and finally died in 24 to 48 hours. 

 There is thus reason to suppose that chlorpicrin might be used with 

 advantage either as a fumigant, or as a spray in the form of an aqueous 

 solution or emulsion against certain pests of cultivated plants. 



Jensen (H.). Control of Lasioderma serricorne and Setomorpha 

 margalaestriata, injurious to Tobacco in Java. — Proefstation voar 

 Vorstenlandsche Tabak, Semarang, 1917, Mededeeling, no. 30, pp. 

 1-29. (Abstract in Mihly. Bull. Agric. Ititell. PI Dis., Rome, x, 

 no. 1, January 1919, p. 127.) 



The position of the tobacco plantations in Vorstenlanden is not 

 favourable to the beetle, Lasioderma serricorne, and the moth, Setomor- 

 pha margalaestriata, the crop in normal times being kept only for 

 six months or less in sheds that are very clean. Eecently the period 

 of storage has been longer owing to lack of shipping, and consequently 

 there has been some danger of infestation. Investigation has shown 

 that carbon bisulphide at the rate of approximately | pint per 35 

 cub. ft. is sufficient to disinfect the sheds, or benzine may be used, 

 provided that the air is thoroughly saturated with it for 5 or 6 days. 

 The fumes of sulphur dioxide or formalin have no effect upon L. serri- 

 corne. The tobacco sheds should be protected by mosquito nets. 



Mackenna (J.). Report on the Progress of Agriculture in India for 

 1916-17, Calcutta, 1918, pp. 72-84. [Eeceived 9th May 1919.] 



The breeding of parasites of cotton boll-worms {Farias spp.) was 

 continued [see this Review, Ser. A, v, p. 316], the opinion now 

 being held that_these belong to the genus Microbracon and not to 



