358 Miscellaneous. 



The seeds damaged by the small white worm lose 28*5 per cent, on 

 the quantity which they should have yielded. The seeds pierced by 

 the weevil in the perfect state sustain a loss of oil equal to 18*2 per 

 cent. From these data M. Focillon has arrived at a mode of calcu- 

 lation by which the loss of oil on a given crop of rape-seed may readily 

 be ascertained. According to these calculations, M. Focillon states 

 the loss on the crop of rape-seed raised by the above-mentioned In- 

 stitution in 1851, at 2800 francs out of 7500. 



The result of experiments made to ascertain the effect of the at- 

 tacks of the insects on the germinative faculty of the seeds is as fol- 

 lows : — The seeds eaten by the larvae of the weevil and moth and 

 those pierced by the perfect weevil do not germinate. Of 100 seeds 

 affected by the small white worm only 52 germinated, whilst out of 

 100 sound seeds the average number was 80. — Comptes Rendus, 

 1852, p. 252. 



Note on a species of Coccus, indigenous to France, which lives on the 

 Common Bean, and appears to be capable of furnishing an abun- 

 dant Colouring Matter which may be used in the Arts. By 

 M. GuERiN Meneville. 



This new Coccus {Coccus Fabce) when crushed in linen or paper 

 furnishes a red colour, sufficiently intense to raise hopes that it may 

 perhaps contain as much colouring matter as the Mexican cochineal. 



"What renders this indigenous cochineal very interesting is, that it 

 would be possible to cultivate it and raise regular crops of it. It lives 

 on Vicia Faba, on which it is so abundant, that I have been able, in 

 a few hours, to collect a considerable quantity of these cochineals, by 

 brushing the plants covered with them over a cloth. I treated them 

 in the same manner as that by which the Coccus Cacti is prepared — 

 killing them in boiling water and afterwards drying them in the sun. 

 By these means I have obtained an article which offers a considerable 

 resemblance to the cochineal of commerce, and may, even now, be 

 the subject of some experiments in dyeing, should the Academy think 

 fit to ask M. Chevreul to undertake them in his laboratories. 



As I brought with me a considerable number of living cochineals, 

 I have been enabled to continue the study of their habits in Paris, 

 and have seen that the myriads of eggs which they laid last autumn 

 were hatched during the winter, and that young ones proceeding from 

 them are able to live without nourishment until they meet with the 

 plants on which they feed. 



I have instituted an experiment on rather a large scale at Sainte 

 Tulle, and I hope this year to raise a sufficient crop of this cochineal 

 to enable experiments to be made on larger quantities, should the 

 results of those which I have ventured to ask of M. Chevreul, give any 

 encouragement to follow out this new application of entomology. 



Some very curious parasites on this cochineal have been discovered 

 this winter, and will probably give occasion for some interesting sci- 

 entific observations. — lb. March 1852, p. 334. 



