166 THE HOT-HOUSE. , [FEB. 



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

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

 the proboscis. Feet eight. They are oviparous. 



This is a pest to almost every kind of plant ; 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 havock on plants ; for this insect, with its proboscis, per- 

 petually wounds the fine or capillary vessels of plants, and extracts 

 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 somtimes prevents the mixture from entering into cer- 

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

 unhurt, 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 

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

 sfiung-e : 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 flues late in an 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 HEMIPTERA. Characters. Rostrum, 

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

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

 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- 

 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 ^ 



