I. \ SECTS, OR DESTROYING THEM. 65 



Collecting the Eggs of Insects. The eggs of insects, after being 

 deposited on the bark or leaves of plants, may sometimes be collected 

 by hand ; for example, when they are laid in clusters or patches, so as 

 to form a belt round the twig, as in the lackey-moth ; or when they 

 are covered with fibrous matter, as in the Bombyx dispar, which lays 

 its eggs in large circular or oval groups, containing 300 or more each, 

 on the bark of trees or hedges, and covers them with a yellow wool. 

 The eggs of the yellow-tail moth are laid on the leaves of fruit-trees, 

 in a long narrow heap, and covered with gold-coloured hair, whence 

 the scientific name Bombyx chrysorrhoea, which makes them very con- 

 spicuous ; but the leaves may easily be collected, and the eggs de- 

 stroyed. The satin-moth, Bombyx salicis, which, in its larva state, 

 feeds on the leaves of willows and poplars, often stripping entire trees, 

 when it becomes a perfect insect, lays its eggs in July, in small spots 

 like mother-of-pearl, on the bark of the tree ; and as they are con- 

 spicuous, they may easily be scraped off. Practical men in general 

 a iv too apt to undervalue the effects of hand-picking, whether of the 

 eggs or larvae of insects ; not reflecting that every insect destroyed by 

 this means, is not only an immediate riddance of an evil, but prevents 

 the generation of a great number of other evils of the same kind. Cir- 

 cumstances have forced this on the attention of the French cultivator, 

 and the following facts will place the advantage of hand-picking in a 

 strong light. In 1837, M. V. Audouin, already mentioned, was 

 charged by a commission of the Academic des Sciences, to investigate 

 the habits of a small moth, whose larva is found to be exceedingly in- 

 jurious in vineyards in France. During the month of August, women 

 and children were employed during four clays in collecting the patches 

 of eggs upon the leaves, during which period 186,900 patches were 

 collected, which was equal to the destruction of 11,214,000 eggs. In 

 twelve days from twenty to thirty workers destroyed 482,000 eggs, 

 which would have been hatched in the course of twelve or fifteen 

 days. The number of perfect insects destroyed in a previous experi- 

 ment, by an expensive process, was only 30,000. (' Gard. Mag.,' 

 vol. xiii. p. 486.) Many insects, however, deposit their eggs singly 

 or in very small quantities, or in concealed places; and the eggs being 

 in these cases very small, they are not easily found. 



Preventing Eggs from being Hatched. Eggs, aiter being deposited, 

 may sometimes be destroyed, or prevented from hatching, by the ap- 

 plication of washes, or a coating of glutinous adhesive matter, such as 

 gum, glue, paste, soil soap, sulphur and clay, or in some cases clay 

 alone. A mixture of lime and water will not always have the effect 

 of preventing the hatching of the eggs ; because, when the egg 

 boprins to vivify and swell with the heat of the spring, the lime 

 ;s and drops off. This, however, is not the case when the lime 

 is mixed with soft soap and cow-dung, which render it adhesive and 

 elastic. Water raised to the temperature of 200 will destroy the eggs 

 of most insects ; and when these are deposited on the bark of the 

 trunk of an old tree, or the well-ripened branches of a young hardy 

 tree, water at this temperature may be applied freely. For young 



