DISEASES OF CITRUS TREES ] 81 



establish itself, and fixes its beak- like mouth, consisting 

 of two mandibles and four bristly appendages, into the 

 green tissues, and in a few hours more it loses its 

 limbs and secretes a mass of white filaments with 

 which it covers itself. In five days it forms the first 

 larval skin, the smaller round or oval black scale 

 already mentioned. This skin gets surrounded by a 

 rim of wax, and very soon follows the formation of the 

 second shield or scale, and when the insect is undergoing 

 the third stage a broad rim of wax is formed all 

 around it. Parlaioria Lucasi like most scale insects, 

 is parthenogenetic and viviparous, and the larvae of 

 the second brood creep out of the mother scale in 

 June. In the first days of August appears the third brood, 

 and the fourth is produced towards the middle of 

 September or a little later, but generally in the first 

 days of October all the larvae of the fourth brood 

 are fixed in their chosen abode. In October the male 

 insects appear in great numbers and the impregnated 

 females after running through their term of life die, 

 leaving a multitude of eggs sheltered beneath the 

 scale, and ready to hatch in the first warm days of 

 spring. 



Parlatoria Lucasi, in Maltese, miscta seuda irkika, 

 is rarely seen on twigs whose bark has lost its green 

 colour but in sheltered situations all the green parts 

 of the tree and the fruit are literally covered with 

 the parasite. Badly infested trees suffer considerably, 

 and large branches may be killed. The fruit is made 

 very unsightly and unsaleable, and is not allowed to attain 

 its full size, but its aroma and keeping qualities remain 

 unaltered. The adult insect is not known to have any 

 parasite similar to those of the larger scale insects, 

 and the short term of the free existence of the larva 

 is another favourable condition for its prodigious increase. 



The "purple scale", Mytilaspis citricola Comstock; 

 ( Maltese = Miscta giulglienia ) is another scale insect 

 6 



