874 FERNS : BEITISH AND FOREIGN. 



being the most subject, while, on the contrary, the 

 smooth-fronded kinds, such as the whole of the 

 division of Eremobrya, Elaphoglossum, &c, are, it 

 may be said, quite exempt. The mealy bug, three 

 kinds of scale, and thrips, are the chief pests, and 

 should be carefully watched. The oblong brown 

 scale is generally the most common, and very quickly 

 overruns the under side of the frond, forming lines 

 along the midribs. Many kinds of fluid mix- 

 tures, powders, and other nostrums, have from time 

 to time been advertised for their destruction, but it 

 too often happens what kills insects also injures the 

 plant, and makes it look unsightly. Fumigation 

 with tobacco is the grand preventive against the 

 breeding of plant-insects ; very slight fumigation 

 destroys the winged male insect of all the Coccos 

 family, and if frequently repeated, the whole in time 

 will become extinct. When the mealy bug gets a 

 head, it is readily got rid of by syringing; not so 

 the scale, it requires to be loosened with a soft 

 brush, or blunt-pointed peg, which, if the weather 

 permit, should be done out of doors, and the plant 

 afterwards syringed, so as to clear away all loose scale 

 and eggs. Scale insects are adherers and suckers 

 only; not so the less conspicuous insect the thrip, 

 which is a small, slender, black, shining insect, with 

 large prominent eyes, and quick in its movements, 

 herding in groups, generally on the under side of 

 the frond, voraciously feeding on the cuticle, which 

 they soon destroy, permanent injury being often done 

 without any indication of their presence till too late) 

 they must, therefore, be carefully watched, and, when 

 seen, at once destroyed by pinching with the fingers. 



