568 FKUIT CULTURE IN TOREIGN COUNTRIES. 



aurantii, attaches itself chiefly to the trunk and larger branches. It 

 forms a thin coating, grayish or yellowish-white in color, with numerous 

 small protuberances that appear to be the reproductive organs of the 

 plant. This parasite is not common, but it is considered very damaging 

 on account of the great tenacity with which it adheres to the trees. 

 There are, however, a number of lichens which attach themselves to the 

 trunks and limbs of the orange tree without causing any apparent in- 

 jury to its growth or to its bearing power. 



Great humidity of the atmosphere, want of light and of ventilation, 

 are known to favor the development of all these cryptogamic forms, 

 and orchards most affected by them are such as occupy low, close situ- 

 ations, and do not have the trees placed at sufQciently large intervals. 

 A sufficiency of space for the free circulation of air and the free admis- 

 sion of sunlight is, therefore, along with proper cultivation, the best 

 preventive. 



A species of phylloxera, first observed on the islands of Naxos and 

 Pares, is known to attack the roots of the orange tree, but this pest 

 has not up to now made its appearance in the Spanish orchards. Lan- 

 derer, the writer who first described this microscopic parasite, recom- 

 mends the use of a solution of carbolic acid, and of a mixture of sulphur 

 and lime, the latter to be spread around the tree. 



The insects causing most damage to orange orchards are several 

 Hemiptera, one of the Diptera, and a few Ooleoptera. 



Among the Hemiptera the chief varieties are the following : 



Chennax hesperidum (Linu.). This insect is oval in shape, \vith hemi- 

 spherical back, and isof a glossy browui.sh hue. Jn the sj)ring the shell 

 of the female contains h large number of eggs resting upon a InytT of 

 whitish dowuy matter. The eggs hatch rapidly, and the sm;ill larvje 

 are turned loose upon the twigs, leaves, and buds, feeding upon the 

 juices of the tree. They finally attach themselves permanently (usually 

 to the lower surface of the leaves), remaining there until the following 

 spring, when a new generation is produced. 



Chermes olem (Ber.). This species is found upon the orange tree, 

 although its more usual habitat is the olive. The shell of the female is 

 hemispherical, of a grayish brown, and has two deep transversal fur- 

 rows, giving it a roughened appearance. 



Ohermes aurantii (Du Breuil). Has been chiefly noticed in Southeru 

 France and in Algeria. It is a large insect, in the shape of an oval, 

 and of a brownish-black hue. 



Chrnncs coooineus (Du Breuil) is hemispherical in shape, of a vivid 

 red color, has two largish autennie of great mobility, and six white legs. 

 This insect confines itself to the leaves, upon which it lays from 10 to 

 15 small eggs, that produce an equal number oJ' small larvre of apearly- 

 whitish color. When they have reached a length of about half a mil- 

 limeter, the insects assume the red coloring; they are frequently moving 

 about with great rai)idity in the vicinity of their meeting places, and 

 arc UHiiiilly found in small swarms or colonies. 



