DISEASES OF CITRUS TREES ] 89 



but being oval-shaped looks much smaller than the 

 Chilocorus, There are also several lesser species of 

 Scymnus which are of frequent occurrence. 



Novius (Vedalia} cardinalis Koeb. This is the 

 natural ladybird enemy of the fluted scale in Australia, 

 whence it was imported in 1889 into the United States, 

 where the fluted scale was causing considerable havoc in 

 the orange groves of California. From America this 

 ladybird was sent to South Africa, Egypt, Portugal and 

 Italy, and was introduced in Malta from Portici (Naples) 

 in 1911, and was set free in the infested gardens at St. 

 Julians. This ladybird is oval -shaped, 3 or 4 m.m. in 

 length, of a uniform red colour with 4 black blotches, 

 two on each side of the elytra, the two posterior spots 

 coalescing along the margin with a narrow black stripe, 

 in the middle between the elytra. The larva is red with 

 black dots, almost as large as the larva of Coccitiella 

 septempunctata, and both the perfect insect and its larva 

 feed voraciously on the I eery a, in a few days clearing a 

 badly infested tree. For the first years after its importa- 

 tion it was considered advisable to cultivate this ladybird 

 artificially, in order to have it always at hand, but now 

 it is perfectly established in most orange groves- of the 

 Island, and its artificial breeding is continued only as a 

 measure of precaution, and to secure early broods in 

 March and April. 



ftnizdoius ventralis is another ladybird about the 

 same size as Novius cardinalis, and feeds on Lecanium 

 Oleae. This is a European species, but does not exist in 

 these Islands, Lecanium Oleae being here kept in check 

 by the other ladybirds above mentioned and also by 

 the scale-moth, Thalpochares Scitula, and by the little 

 chalcidid fly Scutellista cyanea Motsch, and also by 

 other Hymenopterous insects. 



The larvae of the Syrphus flies, a Dipterous genus, 

 feed upon the scale insects and the Orange aphis, but 

 this genus is not known to exist in Malta. Bacca babista, 



