INSECTS, OR DESTROYING THEM. 61 



destroyed in every stage. We shall briefly indicate the different prac- 

 tices which may be had recourse to in different stages, for deterring 

 or destroying insects, by the gardener ; leaving particular details till 

 particular insects come to be mentioned, when treating on the culture 

 of the plants which they attack. We shall commence with operations 

 connected with the perfect insect, and take in succession the eggs, the 

 larva?, and the pupae. 



Deterring the Perfect Insect. The perfect-winged insect may, in 

 some cases be deterred from approaching plants by covering them with 

 netting or gauze, the meshes of which are sufficiently small to exclude 

 the insect, but not too small to prove injurious to the plant by exclud- 

 ing light and air. Wasps and flies are in this manner excluded from 

 vineries and peach-houses while the fruit is ripening. Bunches of 

 grapes against the open wall are also protected by putting them in bags 

 of woollen netting or gauze. Choice plants in pots are sometimes 

 protected from wingless insects by placing the pot containing the plant 

 in the midst of a saucer which surrounds the pot with water which it 

 is found the insect will not cross. The stems of plants, such as dahlias 

 and gooseberries, are sometimes protected by a zone of glutinous matter 

 on wool, tow, or paper, over which the insect will not venture. A 

 remarkable mode of deterring some insects from entering houses by 

 the windows is described in the ' Architectural Magazine,' vol. ii., as 

 practised in Italy, and known even in the time of Herodotus. This is 

 simply to place before the openings of the window a net of white or 

 light-coloured thread, the meshes of which may be an inch or more in 

 diameter. The flies seem to be deterred from entering through the 

 meshes by some inexplicable dread of passing through them. If small 

 nails be fixed all round the window-frame at the distance of about an 

 inch from each other, and thread be then stretched across both verti- 

 cally and horizontally, the network so produced will be equally effec- 

 tual in excluding the flies. It is essential, however, that the light 

 should enter the room on one side of it only ; for if there be a thorough 

 light either from an opposite or side window, the flies pass through the 

 net without scruple. (W. Spence in 'Transact. Entomol. Society,' 

 vol. i.) It would appear to be a general principle, that winged insects 

 may be deterred by meshes of such a size as will not admit them with 

 their wings expanded, and also that insects will not enter from bright 

 light into darkness, more especially if deterred by the slightest obstacle, 

 such as the threads just spoken of. 



Preventing the Perfect Insect from laying its Eggs. Insects may 

 be prevented from laying their eggs on plants within reach by sur- 

 rounding them with a netting or other screen ; or, in some cases, by 

 sprinkling the plant with some liquid containing a very offensive 

 odour. Thus moths are prevented from laying their eggs on goose- 

 berry-bushes by hanging among them rags dipped in gunpowder and 

 tar ; and the watering of such plants as cabbages, peas, etc., overhead 

 with lime or soot-water, weak sewage, and manure water, may deter 

 butterflies from depositing their ova. A fine sprinkling of dry guano 

 will cause ants to forsake their nests and prevent them from coming 



