90 



cause the olives to wither and drop off, and for many years have thus caused 

 an immense reduction in the output of olive oil, particularly in Italy and 

 Sicily. Last year it was estimated to have destroyed 10 per cent, of the 

 total olive crop of Italy. Not only have the producers lost money, but the 

 Government have had to reduce the taxes in the badly-infested districts. 

 The pest has been gradually increasing every year, the returns of 1879-83, 

 when the yield was 3,390,000 hectolitres of oil, have been reduced to 

 2,005,000 in 1895-99. As a large reward has been offered by the Govern- 

 ment for any effective remedy or cure for this pest, all the entomologists have 

 been studying the olive-fly, and carrying out experiments towards its eradi- 

 cation. When it is understood that the olive trees are grown on all kinds of 

 rugged stony hillsides, and the olives are so small that it. is a very different 

 thing to clean up an olive plantation than an orange orchard, the difficulties 

 of the situation can be understood. 



Professor F. Silvestri, of Naples, advocates parasites, but no parasite of 

 any commercial value has been discovered, though several have been bred 

 from the pupae of the olive-fly. 



Dr. A. Berlese, of Florence, has carried out many experiments in trying 

 to attract the flies with sweetened poisoned mixtures, with a certain amount 

 of success. 9 



The olive-fly is one of the smallest species, not more than 2J lines in length. 

 The wings hyaline, with dark nervures, very slightly clouded with yellow at 

 the extremity of the first parallel vein, a small black spot at the extreme tip, 

 and faint clouding of brown on the submarginal cell. The head dull yellow, 

 eyes black, with a black spot below the base of the antennae, the latter blackish 

 at the extremities, a few black bristles on the summit. The thorax black, 

 with the dorsal surface clothed with fine silvery pubescence, so that the black 

 forms three narrow parallel black lines on the thorax ; legs, nude patches on 

 the sides of the shoulders, and the area above and below the base of the 

 wings yellow, inner portion of the scutellurn black, hind portion yellow. 

 The abdomen black, covered with a scattered grey pubescence, the basal 

 segments marked with pale transverse bands, and an irregular parallel bar or 

 blotch of reddish-brown occupying the centre of the apical segments, the 

 apical segment reddish-yellow, with the sheath of the ovipositor black, with 

 the ovipositor reddish. 



As might be supposed, there has been a great deal written about this 

 destructive fly. In " Observations upon recent literature relating to the 

 Olive Pest," Professor Guercio gives a list of thirteen papers published in 

 Italy between the years 1877 and 1907, dealing with the olive fly generally, 

 and there are many other special reports. Dr. Navarro, in his " Memoir 

 relative to the Diseases of the Olive" (published in Madrid, 1898, for the 

 Ministerio de Fomento), gives a very good account of the olive-fly in Spain, 

 which is illustrated with a plate showing how it damages the olive. 



As far back as 1822 Briganti (Atti del Real Institute di Napoli) gave an 

 account of this pest, and four years later (1826), gave a detailed description 

 of its metamorphoses and life history. 



Westwood (" Modern Classification of Insects," 1840) says : " It is known 

 to the natives of Provence under the name of Chiron. It is of a whitish 

 colour ; its mouth is furnished with two hooks ; it at first feeds on the young 

 leaves, but afterwards penetrates into the fruit." Of course, the state- 

 ment that the maggot first feeds upon the young leaves of the olive tree is 

 incorrect. 



