174 TIIE HOT-HOUSE. [Feb. 



mon in hot-houses, as well as upon plants in the open air; it is very 

 minute, so much so as to be scarcely perceptible; generally conceal- 

 ing itself along the veins of the leaves, from whence it skips with 

 great agility on being touched. It is a great enemy to the vine 

 while the leaves are young; and tender, whether they grow in the 

 open air or under glass. The Cape jasmine, as well as many other 

 plants, often fall a prey to these minute insects. 



These may be destroyed by the same methods as the Aphis. 



4. The Oniscus, or iVood-louse. This belongs to the order Ap- 

 tera. Characters. — Antennae, setaceous and bent-mouth, furnished 

 with two palpi. Head, intimately joined with the thorax. Body, 

 oval form, composed of several crustaceous plates. Feet fourteen. 

 They change their skin like many other apterous insects. 



These are very common in the bark-pits, as well as in woods, 

 houses, gardens, &c. but are seldom destructive except to young 

 seedling plants on their first appearance above ground. This, how- 

 ever, may be prevented by dusting the plants, whilst in that state, 

 with fine snutt'or tobacco dust. 



5. The Formica, or Ant. This insect is so universally known 

 as to render a description unnecessary. 



These are often exceedingly numerous in hot-houses, and espe- 

 cially where the Aphides and Coccus hesperidwn abound: for there 

 is a sweet glutinous matter which issues from these insects (being 

 either their excrements, or produced by them from some other 

 cause) that seems to be the principal incitement that draws the ant 

 thither. 



The ant may be destroyed with great facility by setting pots con- 

 taining honey and water, in the same manner as is practised for 

 catching wasps, &c. 



6. The Coccus hesperidum, or Brown Turtle Insect, already 

 described, is not only an enemy to the pine-apple plant, but also to 

 many others both in the hot-house and green-house; therefore I am 

 induced to take notice of it again. 



This insect may be destroyed, whilst young, by fumigation; 

 therefore, where that operation is frequent, they are rarely to be 

 met with. 



Of Fumigating the House. 



The house may be fumigated either by means of bellows invent- 

 ed for that purpose, or by that of a smoking-pot. The most eligible 

 seasons for this business are the spring and autumn, when, if ne- 

 cessity requires, it should be repeated every eight or ten days, till 

 the proper effect is produced. But it may be done at any period, 

 except when there are ripe fruit in the house, as then it would give 

 them a smoky flavour. 



Fumigation is best performed late in an afternoon or evening, 

 and proves most efficacious when the weather is moist and calm; 

 for the smoke is retained much longer in the house when the air is 

 still and the cavities of the roof, particularly those between the 

 squares of glass, filled with moisture. 



