arsenate, copper and soap sprays on the eggs of Polychrosis bolrana, 

 it was found that nicotine, pyridine and Bordeaux mixture gave 

 decisive results, the action of nicotine and pyridine consisting in the 

 slow poisoning of the developing larvae, which died at the moment of 

 hatching, while Bordeaux mixture caused the abortion of the eggs 

 [see this Review, Ser. A, ii, p. 410, and iv, p. 299]. 



Later experiments with lime showed that this substance killed the 

 developing larva in the egg by a slow process of dehydration, only 

 those eggs hatching the development of which was well advanced before 

 treatment. 



Both lead arsenate and sodium arsenate (anhydrous arsenate of soda 

 3, neutral lead arsenate 9, water 1,000) [the figures in this and 

 succeeding formulae, in the absence of any definite indication, being 

 taken to represent parts by weight], gave entirely negative results, 

 all the eggs treated hatching normally. Zinc arsenite, however, while 

 not arresting the development of the egg, resulted in the death of the 

 larvae at the time of hatching. 



Quinoline 10, sulphoricinate of soda 10, water 1,000, had a most 

 decided effect, all the eggs being immediately killed, owing to its 

 caustic action. Pyrethrum 20, black soap 10, water 1,000, destroyed 

 only 18 per cent, of the eggs, these being in the last stage of develop- 

 ment, or partly hatched. Carbolic acid 10, sulphoricinate of soda 

 10, water 1,000, destroyed all eggs without further development. 

 Potassium permanganate 1 in 1,000 water, or potassium permanganate 

 10, sulphoricinate of soda 10, water 1,000, proved useless, all the eggs 

 hatching in due course. Potassium sulpho-carbonate destroyed 63 per 

 cent, of the eggs, nearly all of them being in the first stage of 

 development. Tests of the direct effect on the eggs of gelatine and 

 sulphoricinate of soda, which had been used as media for the application 

 of the poisons, showed that they had no effect on hatching. Pyridine 

 1| per cent., and oleate of pyridine 2 per cent., prevented the hatching 

 of a certain number of eggs, without however stopping embryonic 

 development ; their action resembles that of nicotine and arsenic in 

 poisoning the hatching larvae. Pyridine and pyrethrimi should 

 therefore be useful as external insecticides applied directly to full- 

 grown larvae at a time when unhatched eggs are few or absent. 



These results explain the special efficacy of nicotine as a preventive, 

 since it is able to destroy 80 per cent, of the eggs treated, and also the 

 superiority of nicotined Bordeaux mixture, which prevents the hatching 

 of 88 per cent, of the eggs. 



Le Rhynchite conique (Rhynchites conicus, Illig.) ou Coupe-bourgeons. 



[Rhyncliites conicus, lUig., the Bud-cutter.] BuU. Soc. Etude 

 Vulg. Zool. Agric, Bordeaux, xvi, no. 11-12, November-December 

 1917, p. 126. 



In an article subsequent to that already noticed [see this Review, 

 Ser. A, V, p. 569], M. Bordas deals with the principal means of 

 controlling Rhynchites conicus in apple and pear orchards. These are, 

 the shaking of the trees every two or three days during May and June 

 in order to collect the adult weevils, the collection and burning of the 

 withered shoots that serve to harbour the larvae, and the use of 

 insecticide sprays. A petroleum emulsion that gave good results was 

 prepared according to the formula : — petroleum 2 parts (by weight), 



(C442) c 



