INSECTS, OR DESTROYING THEM. 113 



sometimes be destroyed, or prevented from hatching, by the application of 

 washes, or a coating of glutinous adhesive matter, such as gum, glue, paste, soft 

 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 begins to vivify and swell with the heat of the spring, 

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

 lime is mixed with soft soap, which renders it 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 shoots in general the temperature should not exceed 130 

 or 150. It should be remembered that insects, in depositing their eggs, 

 always instinctively make choice of places where the newly-hatched insect 

 will find food without going far in search of it. Hence they never lay them 

 on walls, stones, glass, boards, or similar substances ; and therefore the atten- 

 tion of gardeners, when searching for ova, should be directed much more to 

 the plants which nourish the insects, than to the walls or structures which 

 shelter the plants. (See 311.) 



360. Collecting or destroying Larvae. Insects are much more injurious to 

 plants in their larva state than they are in any other ; because, as we have 

 already seen (312), it is in this stage of their transformations that they chiefly 

 feed. With the exception, however, of several of the wingless or crawling 

 insects, and certain bugs and beetles, larvae are in general not difficult to dis- 

 cover, because, for the most part, they live on those parts of plants that are 

 above ground ; but some live on the roots of plants, and these are among the 

 most insidious enemies both of the gardener and the farmer. The ver blanc, 

 or larva of the cockchafer, in France, and that of the wire- worm, in England, 

 are perhaps the most injurious of all underground larvae, and those over 

 which the cultivator has least power. Underground larvae may be partially 

 collected, but not without much care and labour, by placing tempting baits 

 for them in the soil. As they live upon roots, slices of such as are sweeter 

 and more tender may be deposited at different depths and at certain dis- 

 tances, and the places marked, and the soil being dug up once a day, the insects 

 may be picked off and the baits replaced. Slices of carrot, turnip, potato, and 

 apple, form excellent baits for most underground larvae. Such as attack leaves 

 as, for example, those of the gooseberry may be destroyed in immense 

 quantities by gathering the leaves infested by them, as soon as the larvae 

 become distinguishable from the leaf by the naked eye. Instead of this 

 being done, however, it too frequently happens that the larvae escape the 

 notice of the gardener till they are nearly full grown, and have done most 

 of the mischief of which they are capable. Hand-picking has been found 

 most serviceable in preventing the injury caused by the blak caterpillar on 

 the turnip leaves, which, in certain seasons, has proved destructive of the 

 entire crop. It may also be applied to the destruction of the cabbage cater- 

 pillars. Here, also, we may notice the beneficial effects of picking out and 

 destroying young onion plants infested by the grub of the onion-fly. This 

 ought to be done as soon as the plants appear sickly, because the grubs 

 arrive at maturity in a very short time ; and, by destroying the plant, future 

 generations of the fly are prevented. Grub-eaten fruit ought also to be 

 picked up as soon as it falls to the ground, before the enclosed grub has 

 time to make its escape into the earth, and which it would do in a very short 



