CULTIVATION. 341 



and syringing the plant. They are generally found 

 on species of Adiantum, Pellcea, Platyloma, Doryo- 

 pteriSf Hemionites cordifolia, and other genera having 

 fronds of a smooth, chestnnt-brown colour. Within 

 the last twenty years a small, white-winged insect, like 

 a midge, has made its appearance (supposed to have 

 been first introduced with imported plants to Kew) . 

 They congregate on the under side of the fronds, and, 

 when the plant is moved, dart off like a flock of 

 white pigeons. At first^it was supposed to be harm- 

 less ; but such is not the case, as it has been found 

 to feed on the cuticle like thrips ; but they are not so 

 easily caught. Repeated tobacco fumigation destroys 

 it.* Red spider seldom attack Ferns ; when such is 

 the case, it is a sure sign that the air of the house 

 is too dry. 



Few plant-houses are exempt from the well-known 

 cockroach, which when once introduced is one of the 

 greatest of pests. They increase and multiply most 

 rapidly, and are most voracious feeders, eating and 

 gnawing the fronds of Ferns, old and young, often 

 completely in one night spoiling fine plants; there- 

 fore war in all its forms must be waged against 

 them. They are night marauders, hiding and breed- 

 ing in crevices of masonry in dark places, generally 

 near the furnaces, or hottest parts of the heating-pipes, 

 and are even found lurking amongst the drainage, in 

 large pots, from which they issue at dusk to commence 

 their ravages. Many expedients are resorted to for 

 their destruction, such as attacking them in their day 



* This insect has been described and figured in the 

 Gardeners' Chronicle, of 1856, by Mr. Westwood, under the 

 name of Aleyrodes vaporariorum. 



