PREVIOUS WORK WITH INSECT PARASITES. 19 
Insects of Missouri, he advocated the collecting of the winter cases of 
the destructive insect and placing the cases in small vessels in the 
center of a meadow or field, away from any fruit trees, with the idea 
that the worms would be able to wander only a few yards and would 
perish from exhaustion or starvation, while their parasites would 
escape and fly back to the fruit trees. It is stated that this method 
was put in practice later by D. B. Wier with success. 
A French writer, F. Decaux, the following year made practically 
the same suggestion with regard to apple buds attacked by Anthono- 
mus. He advised that instead of burning these buds, as was gener- 
ally done, they be preserved in boxes covered with gauze, raising the 
latter from time to time during the period of issuing of parasites so as 
to permit them to escape. In 1880 he put this method in practice, 
and collected in Picardy buds reddened by the Anthonomus from 
800 apple trees, and thus accomplished the destruction of more than 
1,000,000 individuals of the Anthonomus, setting at liberty about 
250,000 parasites which aided the following year in the destruction of 
the weevils. The following year the same process was repeated, and, 
the orchards being isolated in the middle of cultivated fields, all serious 
damage from the Anthonomus was stated to have been stopped for 
10 years.” 
Practically the same suggestion was made later, in 1877, by J. H. 
Comstock, in regard-to the imported cabbage worm (Pontia rape L.). 
Comstock deprecated the indiscriminate crushing of the chrysalids 
collected under trap boards, on account of the large percentage which 
contained parasites. He recommended instead the collecting of the 
chrysalids and placing them in a box covered with a wire screen which 
should permit the parasites to escape and at the same time confine the 
butterflies so that they could be easily destroyed. The same author, 
in his report upon cotton insects,® recommended a similar course with 
the pupe of the cotton caterpillar (Alabama argillacea Hiibn.). 
Riley later recommended the same plan for the bagworm (Thyridop- 
teryx ephemereformis Haw.); Berlese in Italy recommended it for the 
grapevine Cochylis, and Silvestri for the olive fly (Dacus olex Rossi), 
for Prays oleellus Fab., and for Asphondylia lupini Silv. 
Writing on the Hessian fly, Marchal has pointed out that the 
destruction of the stubble remaining in the field after harvest may 
have unfortunate consequences, for if this is done a little late there is 
a risk that all of the destructive flies will have emerged and aban- 
doned the stubble, exposing to destruction only the parasites whose 
part would have been to stop the invasion the following year. Mar- 
chal also points out that Kieffer has shown that one of the measures 
! Riley, C. V. Fourth Report on the Insects of Missouri, p. 40, 1871. 
2 An excellent article covering these general questions was published by Decaux in the Journal of the 
National Horticultural Society of France, vol. 22, pp. 158-184, 1899. 
’ Cotton Insects, pp. 230-231, Washington, 1879. 
