96 



INSECTS. 



order of insects, having two wing cases which shut together, 

 and form a longitudinal suture down the back of the insect. 

 The Chrysomela" has the antennae clavate, thicker to- 

 wards the tip ; the club soHd or inflated ; the body ovate, im- 

 marginate. The "Altica" belongs to the family Saltatoriae 

 of the Chrysomela genus, having the posterior thighs much 

 thicker than the others, and incrassated and formed for leap- 

 ing. The wing cases are yellow, with the margin entirely 

 black. 



This genus of insects are very numerous ; and both in the 

 larva and in the perfect state they are found in woods and 

 gardens, and feed on the leaves of trees and plants, the ten- 

 der parts of which they devour, and reject the fibres. Some- 

 times they infest the cotyledons only, and are very destruct- 

 ive. They are ruinous to the turnip plant when it has 

 only put forth the first leaf : the number being in myriads, 

 a whole field is often wholly consumed in less than one day 

 of favourable sunshine. The leaf of the plant is either wholly 

 devoured, or it is so very thickly perforated with holes, that 

 the growth is ruined. A particular temperature is required 

 to produce the fly, and consequently its attacks are not re- 

 gular, but are directed by the seasons. 



Various remedies have been used, and many more have 

 been suggested in order to prevent the devastations of this 

 insect. Sowings of soot and of quicklime, and decoctions of 

 herbs, and sprinklings of urinary liquids, have been tried in 

 vain. It has been suggested to squirt boiling water on the 

 drills from a water-cart. But, if hot water did kill the ani- 

 mals, it might also injure the plants in that tender state. The 

 most effectual preventive is to push the plant very quickly 

 beyond the tender state, by means of the land being in very 

 fine tilth, and the manure being already in an active state to 

 stimulate the growth. When the second or the rough leaf of 

 the plant is put forth, the growth is safe, as the fly never 

 touches them. 



3. The Aphis, or plant louse, is a genus of insects belong- 

 ing to the order " Hemiptera " of zoology, having the upper 



