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cool and thus helps it to remarginate. A well kept orange tree 

 should be treated in pruning so as to assume a low hemisphserical 

 form, which renders it more productive, more easy of access, and less 

 liable to be damaged by bad weather. 



Diseases. 



The diseases to which the orange tree is subject may be divided in- 

 to three large groups (a) Diseases of animal origin which are caused 

 by animal parasites (b) Diseases of vegetable origin, caused by fungus 

 parasites, and (c) Intrinsic diseases which are crused by errors of as- 

 similation or by unsuitable surroundings. 



The diseases of animal origin are, by far the most important as they 

 have a direct bearing on the crop. The number of insects with which we 

 have to deal in the orange is legion, and they are continually^ increasing. 

 Their havoc may be shown by stating that an orange grove infested 

 with the fruit fly has about 1/3 of its crop ruined by these insects; 

 and this year I have known several orange merchants re! using to buy 

 the crop of the orange groves of Casal Lia, Balzan and Attard because 

 the fruit was hideously disfigured by the new scale insect Parlatoria 

 Lucasi, Some years ago many orange groves were so badly infected 

 with the Mytilaspis that many branches withered up and in some 

 cases the trees had to be removed. On the other hand there are many 

 insects whose beneficial influence is much felt in the orange grove and 

 which are the truest friends of the orange grower. We shall give a 

 brief description of the most important of both. 



Among the Coleoptera, the Cockroach order, there are some insects 

 which gnaw into the trunk of the orange tree. Although these in- 

 sects are common in America and in several European countries, I 

 have never noted any borer of the living wood of the orange tree in 

 these Islands. But there is a Coleopterous insect of great beauty 

 which feeds on the leaves and blossoms of the orange tree. This in- 

 sect Cetonia Aurata is an inch in length, has its wing-cases (elitrse) of 

 a bright green colour. Its head and the upper surface of the Thorax 

 are of the same colour. Its abdomen is bright purple. It is by no 

 means a very common insect and the damage caused by it is hardly 

 noticeable The Lencocselis funesta and the Epicometis squalida are two 

 Colepterous insects which sometimes may be met with on the orange 

 blossoms, although they never gave any real cause of complaint to 

 the orange grower. 



The Coccinellidse, a family of the Coleoptera are represented in our Is- 

 land by some very useful friends of the orange groves. Thus Chilochorus 

 bipustulatus, Exhocomus quadripunctatus, Cocciuella septempunotata, 

 Coccinella undecimnotata, Adalia bipuuctata, Halizia decempunctata 

 and one or two species of Scymnus, are particularly the first two in 

 the list, common denizens of the orange groves. The larva of the 

 Chilochorus bipustulatus lives hy eating the young larvae of many parasi- 

 tes of the orange tree, particularly the larvae of the Scale insects. In its 

 adult state it is of ths size and form of a grain of wheat, covered all 

 over with black hairs, and having a transverse white stripe in the 

 middle of its back. Arrived to maturity it fixes itself on the under 

 surface of a branch or leaf and becomes a chrysalis. There it under* 

 goes the usual metamorphosis and in a few days sallies-forth a perfect 



