14 ROYAL SOCIETY OF CANADA 
soon as the heads formed) are destroyed by the cattle eating them, or 
they dry up with the clover hay which has been cut before they were 
mature enough to leave the heads of clover and go into the ground to 
complete their stages. By leaving the clover standing in the fields till 
the end of June a sufficient time elapses for this latter process to take 
place, and the perfect flies emerge again just in time to lay their eggs in 
the opening flowers of the second crop. In this way, the seed of the 
second crop is destroyed as well as the first. The discovery of this prac- 
tical remedy I formerly attributed to a Canadian farmer ; but I find 
it, together with many other suggestions of great value in economic ento- 
mology, was undoubtedly first suggested by Mr. Howard. 
SYSTEMATIC (CO-OPERATION. 
Finally, let me bring before your notice one instance exemplifying 
how combined systematic effort may work wonders even in an apparently 
hopeless case. 
Of the many injurious insects introduced at various times from the 
old world, not one has, in as short a time, attracted so much attention, 
been so great a cause of anxiety, or has been so systematically fought as 
the Gypsy Moth, since it appeared in vast numbers in the state of Massa- 
chusetts in 1889. As a practical object lesson of the value of scientifically 
directed effort to overcome an insect enemy which had been allowed to 
increase unnoticed until it had assumed almost overwhelming proportions, 
the campaign which has been so successfully carried on for the last four 
years by the Gypsy Moth Department of the State Board of Agriculture 
of Massachusetts, is of very great interest to all economic entomologists. 
Mr. L. O. Howard, the United States Entomologist, one of the best 
qualified to express an opinion, says, in his recent address as president of 
the Association of Economic Entomologists, as follows: “The work 
upon the Gypsy Moth which has been done by the State of Massachusetts 
since 1889, is one of the most remarkable pieces of work, judging by 
results, which has yet been done in economic entomology. The opera- 
tions have been carried on by a committee of the State Board of Agricul- 
ture, and the means have been furnished by large appropriations by the 
State Legislature. Three hundred and twenty-five thousand dollars 
have already been appropriated. A territory comprising something over 
100 square miles was infested by the insects, which occurred in such extra- 
ordinary numbers as to destroy many trees, and almost to threaten the 
ultimate extinction of living vegetation, not only within the infested 
territory, but in all localities to which it might spread. The infested 
territory has been reduced by one-half, and within the districts in which 
the Gypsy moth at present exists, it is, practically speaking, a compara- 
tively rare species. The future of the insect is, however, problematical. 
