FERN-PESTS. 1 7 1 



L. platycerii (PL 22, Fig. 5) is found on the Stag's- 

 Horn Fern (Platy cerium), where it does much 

 mischief. The Aspidiotus bromelii is another of 

 these pests. The scale-lice are themselves some- 

 times attacked, as is the Aphis, by parasites. A 

 minute ichneumon-fly pierces the outer shell of 

 the scale, and deposits its eggs within. These are 

 hatched, and the larvae, feeding on the scale-con- 

 tents, soon destroy their host. When perfected, 

 the little ichneumons fly away to repeat this pro- 

 cess on other scales. Dr. Packard, judging from 

 his observations, thinks that a great many scale- 

 lice are thus destroyed. 



The red spider (Tetranychus telarius) ought not 

 to be found in any fern-house, as its presence 

 plainly shows that the temperature is too high, 

 and that the atmosphere of the house is not 

 sufficiently moist. The red spider, as well as the 

 Thrips, will first attack plants which are not in 

 their most healthy condition, as is the case when 

 plants which naturally require a temperate heat 

 are kept in the tropical house. Among the ferns 

 most frequently assailed are Pell&a hastata, Lo- 

 maria ciliata, L. gibba, and Aspidium falcatum. 



The red spider belongs to the family of mites. 

 It can hardly be seen without a glass ; but, when 

 collected in quantities, the insects give the fronds 

 a rusty appearance ; and, if the fingers are drawn 

 over the fronds, they will be stained a reddish 



