168 



{Psidium guajava), Mitnusops elengi, Noronhia emarginata and Chinese- 

 orange (Citrus japonica), fruit-fly larvae develop abundantly and are 

 but slightly parasitised, as is shown in another table recording the 

 percentage of larval parasitism in various fruits. Certain characters 

 of these fruits prevent the parasites from reaching the larvae within, 

 and this in part explains the constant presence of this pest, in spite 

 of the establishment of parasites well adapted to the conditions of the 

 coimtry and of great prolificness. The guava, which grows wild over 

 most of the uncultivated parts of the island and fruits throughout 

 the year, is a favourite host of the fruit-fly. Infestation of this fruit 

 is not easily detected until it has decayed, while the nature of the fruit 

 protects the larvae from parasitic attack and thus it constantly 

 liberates great numbers of flies throughout the year. 



A comparison of fruit-fly parasitism data secured during the years 

 1914-1916 would indicate that the parasites now present in the Territory 

 have reached their maximum degree of development and can hardly 

 be expected to attain a greater control of the fruit-fly than that 

 evidenced in 1916. It is still hoped, however, that Tetrastichtis 

 gijfardianus, Silv., may afford some measure of control. Certain 

 valuable points in favour of this parasite may enable it, after further 

 acclimatisation and adaptation to new environment, to surpass the 

 work of the Braconids and thus increase the total average parasitism. 



Hecke (G. H.). Response and Report to the Fiftieth State Fruit 

 Growers' Convention. The Insectary Division. — Mthlij. Bull. Cat.. 

 State Commiss. Hortic, Sacramento, vii, no. 1 & 2, January- 

 February 1918, pp. 6-7. 



The greater part of the work of the laboratory during the year 

 consisted of the rearing and distribution of the natural enemies of 

 the citrophilus mealy bug [Pseudococcus citrophilus], especially of 

 the Sicilian mealy bug parasite [Paraleptomastix ahnormis]. 



Attempts were made to parasitise the sugar-beet leaf-hopper 

 [Eutettix tenella] by the introduction of an egg-parasite from Austraha, 

 where it attacks 90 per cent, of the eggs of allied leaf-hoppers. The 

 work is to be continued next year. Much attention was given to the 

 control of the Argentine ant [Iridotnyrtnex humilis] in orchards, this 

 insect being indirectly an orchard pest owing to its habit of protecting 

 scale-insects from their natural enemies. 



About 80 millions of Coccinellids were sent out to farmers during 

 the season for the control of Aphids. 



Serious attempts are being made to control insect pests by means 

 of natural enemies, rather than by spraying, a method which cost 

 the farmers of California £800,000 during 1917. 



Gill (J. B.). The Pecan Leaf Case-Bearer.— C/./S. Dept. Agric, 

 Washington, B.C., Bull. no. 571, 15th December 1917, 28 pp., 

 3 plates. [Received 25th February 1918.] 



Acrohasis nebulella, Riley (pecan leaf case-bearer) is one of the 

 principal insect pests of the pecan nut (Carya olivaeformis). The 

 synonomy of this moth is discussed. It has been erroneously treated 

 by some authors as a variety of Mineola indiginella, Z. It is \videly 



