THE PISTACHIO-NUT THEE ] 399 



of flower buds and to interfere with the productiveness 

 of the tree in the following year. The diseased leaves 

 may be picked and burned, and the soil under the tree 

 digged deeply in autumn to bury the hybernating spores 

 along with the decaying foliage. Several species of mould 

 attack the ripe fruit if not dried properly before storage, 

 but are really of a saprophytic nature. 



A common and very curious parasite of the terebinth 

 and to a less degree of the pistachio- nut tree, is Pemphi- 

 gus cornicularius Pass., a minute Hemipterous insect 

 which deposits an egg in the terminal bud of a young 

 shoot as soon as it has stopped growing, and a gall is 

 produced having the shape of a cylindrical horn-like 

 production, from 8 to 15 cm. long, and i to 2 c.m. in 

 thickness. Within it there is a numberless progeny of the 

 original egg, procreated parthenogenetically. These 

 minute insects are of a dull lead colour, covered by a 

 whitish powder, and many of them are provided with 

 wings and fly off in a small cloud as soon as the gall is 

 torn open. In rare instances two horn-like galls are 

 produced from the same bud, but as a rule they are 

 solitary, although the same tree may bear quite a large 

 number of these singular productions. The same gall is 

 also found on the pistachio-tree, but then it is generally 

 very long (15 to 20 c.m.) and more or less twisted into a 

 spiral or curved like a scythe. It was generally supposed 

 by gardeners that the fertilization of the tree was due in 

 great measure to the presence of these galls (scorna- 

 becco), but it is now recognised even by the more ignorant 

 that these galls are merely the result of parasitism, and 

 have no connection with the tree's fertility. 



Other forms of galls of the terebinth and the 

 pistachio-tree, in Sicily and Italy, are produced by Pem- 

 phigus utricularius Pass., P. semilunarius Pass, and 

 P. foLlicularius Pass, but they are not known to exist in 

 these Islands. Aploneura Lentisci Pass, is another 

 Hemipterous insect which causes the formation of galls 



