78 
Ai)plud Entomologif 
and the predaceous ground beetle Calosoma caldimn Fabr. Of these, 
the Polistes, which is predaceous on the larvae of the cotton worm, is 
stated to be the most important (Ballou, 1907, p. 235 ; 1912, p. 315). 
The most extensive campaign yet attempted against any destructive 
insect is that organised by the Bureau of Entomology of the U. S. 
Dept, of Agriculture with reference to the Gipsy moth (Howard and 
Fiske, 1911 ; Fiske, 1913). Introduced from Europe into Massachusetts 
in 1868 it multiplied and spread with e.xcessive rapidity, owing largely 
to the fact that although in Europe it is held in check by various 
parasites, these latter were not introduced into America along with the 
host. The work of Fernald and Forbnsh, in 1896, demonstrated that 
the Gipsy moth is attacked in America only to a very small degree by 
indigenous species of parasites and predaceous insects. They found 
that the maximum numbers of the Gipsy moth destroyed by parasites 
was 10Yo> and that on an average it was nearer 2''/o. Studies on the 
same lines, made in several European countries, revealed the fact that 
over 80 % of individuals are destroyed by parasites. In the case of 
the Gipsy moth, as well as in many other Lepidoptera whose larvae are 
leaf-feeding, that have been studied in America, it is found that control 
by means of parasites must come about through the agency of a variety 
of species working together harmoniously (Howard and Fiske, 1911, 
p. 105). This is an important generalization, as certain other species 
of destructive insects have been successfully controlled through the 
agency of single species of parasites. It is, therefore, the aim in 
America to secure the firm establishment of a sequence of the egg, the 
caterpillar, and the pupal parasites of the Gipsy moth under analogous 
conditions which obtain in Europe. The study and importation of 
these parasites have now been going on for a number of years and, until 
the object is either achieved or proved to be impossible. Dr Howard 
states that the fight will not be abandoned. On p. 77 is given a table 
showing the chief parasites of the Gipsy moth in Europe. Opposite 
the name of each parasite is a dotted line showing the stages in the 
life of the Gipsy moth during which it may be attacked by the parasite 
in question. The solid lines denote the stages in its life during which 
the Gipsy moth is likely to contain the parasites in its body. At the 
head of each vertical column is stated the approximate number of days 
the Gipsy moth spends in each stage of development. 
