Feb.] THE HOT-HOUSE. j-<3 



2. The Acarus, commonly called the Red Spider. This is of 

 the order Aptera. Characters. Eyes placed on the sides of the 

 head, remote from one another. Mouth or proboscis, formed by a 

 small pointed rostrum inclosed in a sheath. Antennas, shorter than 

 the proboscis. Feet eight. They are oviparous. 



This is a pest to almost every kind of plants, for this insect is 

 not only pernicious to most plants kept under glass, but also to 

 many growing in the open air. 



In hot dry weather the increase of these insects is exceedingly 

 rapid, and when they become numerous, they, by various means, 

 commit great havoc on plants; for this insect with its proboscis, 

 perpetually wounds the fine or capillary vessels of plants, and ex- 

 tracts their nutricious juices. It also works a web about the leaves 

 and over the tender buds and tops of the plants, in such a manner as 

 nearly to suffocate them, and prevent their vegetation. 



This insect does not seem to be affected by fumigation made with 

 any ingredients hitherto discovered; and it is probable that the ap- 

 terous insects, or those without wings, are not so much affected by 

 fumigation as the winged tribe. 



However, the mixtures recommended for destroying the insects 

 on the pine-apple, will have the same effect on this. Plants greatly 

 infested, and growing in pots, when their tops are not very large, 

 may with great facility be dipped in a convenient vessel filled with 

 those mixtures: the top of the plant need only remain a short time 

 therein, and it should then be placed in a shady place to prevent 

 its drying too rapidly. 



These insects very frequently reside on the under side of the 

 leaves, and, when very numerous, they work so thick a web there- 

 on, that it sometimes prevents the mixture from entering into cer- 

 tain hollow parts of the leaves, by which means a few escape un- 

 hurt; in which case it will be proper for the plants to undergo the 

 same operation the succeeding afternoon, which will most assuredly 

 destroy all that escaped before. 



Large or climbing plants, when their leaves are large, as for in- 

 stance the vine, must be dressed with the mixture by means of a 

 sponge; this has the appearance of a tedious operation; but in a 

 dark day when the house is not very warm, a person will make 

 considerable progress therein in the course of a few hours. 



The keeping of the house in a moist state, by watering the. walks 

 and Hues late in the evening, and the frequent sprinkling of the 

 plants with water, contributes to retard the progress of these insects, 

 which are very impatient of much moisture. This reduces them to 

 a temporary state of inaction, but will not destroy them. 



3. The Thrips. Order IIemiptera. Characters. Rostrum, 

 small and obscure. Antennae, as long as the thorax. Body slender, 

 of an equal thickness in its whole length. Abdomen reflexible, 

 being generally bent upwards. Wings four, incumbent on the back 

 of the insect, narrow in proportion to their length, and cross one 

 another at some distance from their base. Feet six, the tarsus of 

 each foot having only two articulations. 



This is also a very pernicious species of insect, and is very com- 



