Insects, etc., Injurious to the Plum. 



389 



Edwards (6) does not appear to have been acquainted with the 

 economic literature of this subject, for lie states in Ids work on the 

 Hemiptera-Homoptera of the British Isles (p. 3) that "none of the 

 Honioptera-Cicadina can be said to l)e of any economic importance 

 in Britain ; certain species, as Fhikcnifs spitrn'irin, Chlorifa riridida, 

 Euptcryx auratiis, etc., sometimes swarm in gardens, and elm and 

 beech trees are generally tenanted by countless numbers of TjipUo- 

 c//hi(hr, but it does not appear they do any real harm in any stage." 



The Tiiphloey'bido: are small leaf hoppers, which form a very 

 homogeneous group, and some, such as 

 the Tjiphlociilja qnercioi, are very gaily 

 coloured ; otliers, as the two Chlorita:, 

 are more uniform in appearance. 



No less than twenty species of 

 Tijplilocijhi are known to occur in 

 Britain. One species is described from 

 plums (T. pruiii, Edw.), another from 

 nuts (T. avclluncc, Edw.). Neither of 

 these liave been so far observed by me 

 on fruit trees in any numbers, and in 

 many orchards and plantations visited 

 none could be found at all. 



It is strange that one of the species 

 that has done so much harm to fruit 

 trees should be an oak feeder. At 

 least, it has been identified as such by 

 ]Mr. Distant, and it certainly answers 

 the description of Tijplilofiiha qi'cn ./.s 

 given by Edwards, altliough his figure 

 does not quite agree with any specimen 

 I have. The series in the Douglas 

 and Scott collection in the Pjritish Museum, however, all agree with 

 those that have been sent me. 



The damage done by these leaf hojipers is very marked, and has 

 been referred to by various writers abroad. 



In the case of apple and plum the insects, by means of their 

 probing proboscides constantly being inserted into fresh tissue and 

 constantly sucking out the sap, produce on the leaves, first, minute 

 pale spots, which gradually increase until the leaves become more or 

 less entirely silvery green, or grey, or marbled. To such an extent 

 have I seen this effect that anyone would have thougiit, at a distance, 

 that the trees were suffering from Silver Leaf disease. 



FIG. ioO.— DAJlSuN sruAv, siiowi: 

 DAMAGE BY LEAF HOPPERS. 



Note pale silvery hue of leaves. 



