76 Applied Entomology 
discovered that, in those countries where a pest is innocuous, its num¬ 
bers are to a large extent kept down by parasitic insects which destroy 
it. By importing these parasites into a country, where the hosts are 
little affected by parasites, and therefore causing widespread damage, 
remarkable success in certain instances has been achieved. One of the 
most striking cases of this nature is the importation of the Coccinellid 
beetle Novius cardinalis from Australia into California, to control the 
orange scale Icerya ‘purchasi, which was devasting the orange and lemon 
groves of that country (Howard and Fiske, 1911, pp. 24-27). All 
attempts to combat it by means of insecticides proved useless, but the 
imported beetle adapted itself to its new surroundings so effectually 
that, in less than one year, the scale insect was reported by Prof. Riley 
to be no longer committing serious damage. This was in 1889, and 
the scale is still kept effectually under control. It is further noteworthy 
that it has been similarly dealt with in Florida, New Zealand, Portugal, 
Cape Colony, Formosa, Egypt, the Sandwich Islands, Italy, Syria, and 
quite recently in France and Malta. In Italy, mulberry cultivation has 
been threatened by the scale insect Diaspis pentagona. In 1891 the pest 
assumed such serious proportions that the Italian Government passed 
a legislative measure compelling mulbei'iy cultivators to use all avail¬ 
able means of coping with it. This, however, proved of little efficacy, 
and it was not until Prof. Berlese of Florence introduced a species of 
Chalcid fly {Prospatella herlesei) from America into Italy that much 
headway was made. The results of the importation have proved most 
successful and Prof. Berlese (1913, p. 697) believes that by the end of 
the year 1914 the Diaspis scale will no longer be a serious enemy to 
Italian fruitgrowers. 
In the Sandwich Islands the sugar cane has suffered serious depre¬ 
dation from leaf-hoppers accidentally imported there from Australia, 
In 1904 Perkins and Koebele visited Australia in order to investigate 
all likely parasites of the leaf-hoppers. Over 100 species of these 
parasites were brought to light as the result of their work, and five 
species thereof are stated to be acclimatised in Hawaii. They are all 
minute Hymenoptera, preying upon the eggs of the leaf-hoppens, and 
the practical results of their importation are stated to be quite satis¬ 
factory (Howard and Fiske, 1911, p. 35). Another interesting example 
of successful control is found in the case of the cotton worm {Alabama 
argillacea) in the island of St Vincent. The insects which appear 
chiefly responsible for the destruction of the cotton worm are the wasp 
Polistes annularis L., a Chalcid dy—probably Chalcis annulatus Fabr.— 
