FERN GROWING 143 



had fed very much on the roots ; but the plants all recovered. 

 Again, in 1 891, on repotting the specimen Adiantums, it was 

 found that these grubs had eaten into the very hearts of the 

 plants, so that the specimens were divided by them into small 

 pieces. The author counted as many as one hundred and 

 seventy in one Adiantum pan, and there was not a single 

 plant that had not dozens of these grubs. Although their 

 ravages caused the plants to be some time in recovering, most 

 of them were saved. Other small flies and beetles are destruc- 

 tive to the fronds. An insect known as the frog-hopper 

 (Thrips ochraceus), from its snipe-like flight, feeds on the 

 upper green surface of the fronds, very much disfiguring the 

 Polypodium vulgare. It is readily observed on touching a 

 frond, as it instantly flies off and settles on the under-side of that 

 or another frond. Varnished wire-netting (a substitute for glass) 

 is invaluable as a frog-hopper trap, owing to the stickiness 

 of the varnish. Tobacco water, fir-tree oil, and fumigating 

 kill these insects ; but others arrive, and have to be continually 

 looked for. The froth-hopper or cuckoo spit {Teltigonia 

 spumaria) is only occasionally found on the fronds ; it is ' 

 recognised by its froth. The red spider [Acarus tellarius), 

 the mealy bug {Coccus adonidum), the oleander scale [Aspidi- 

 otus nerii), thrips {Thrips adonidum), and the plant louse 

 {Aphis, several species) are all more or less troublesome when 

 the Ferns are in a greenhouse. 



As regards destructive slugs, the author wishes particularly 

 to except the Testacella haliotidea (Draparnaud), and its varie- 

 ties scutum {So-w&rhy), pci'llida (Cockerell), and aurea (Cockerell), 

 and also Testacella Maugei (Ferussac) ; these are friends instead 

 of foes ; they are easily recognised by the small shell on the 

 top of the slug at what we may call the tail end, though in 

 reality this is not the tail. In 1882 the author. sent a number of 

 specimens to his friend Dr. Gwyn Jeffreys, for he had found 

 them in abundance at Shirenewton, Chepstow, Newchurch, 



