The habits of the larvae having been to a large extent ascertained, it became evident that the removal of the fences across streams, and of stationary logs and "snags" would, in a large measure, prevent the breeding and reduce the number of adults. This is a matter for local or general legislation, rather than individual adoption, and, as shown in recent reports, the general government has become responsible for a rather widespread buffalo-gnat supply in north-west Louisiana, which would be greatly relieved by the removal of an enormous raft of logs in Bayou Pierre.

It is in this direction of prevention that our best energies should be exerted, for in this direction the promise of the future is great. Effort here should be founded, as just stated, upon the most accurate knowledge of life-history and habits, and in its broadest application it depends for its successful outcome upon county, state or national legislation and the intelligence and entomological knowledge of the officers entrusted with the carrying out of such regulations or laws as may be enacted. And right here is the great danger of the future. Even the most enlightened legislative bodies are liable to error and, in this country particularly, the all-pervading influence of party politics will bring about the appointment of incompetent officers. Even the international conference at Berne, through insufficient knowledge of details, passed unjust and over-stringent regulations regarding the grape phylloxera which have injuriously affected the plant exporters of this country, while the incompetence of appointees has almost invariably lessened the ♦ good accomplished even where the legislation was wise.

The several districts of California, in spite of stringent quarantine laws, have, by incompetence of inspectors, admitted injurious scale-insects from Florida and from abroad, while the very recent measures adopted by the legislature of Massachusetts for the suppression of the gipsy moth (Ocneria dispar) bid fair, as I am informed upon reliable authority, to utterly fail of their result by the appointment of a commission to carry them into effect composed of a country doctor, a Boston business man and a market gardener - all three without the least entomological knowledge. When applied entomology becomes coupled with politics, there is always danger that it will fall into the hands of incompetents, or worse - men who owe their influence to politics and political methods.

In the direction of wise legislation, however, there is much to be done in the immediate future. There is always danger of the importation of foreign pests, and the different sections of our own country should be on their guard against the introduction of injurious insects from other sections. A whole catalogue of pertinent illustrations might be cited.

(2) The greatest advances of the past few years in the line indicated by the second category, have been in the discovery of the applicability of arsenical poisons against biting or masticating insects; in the extension of their use against many species which were not at first thought to be amenable to treatment by them ; also in the discovery of simple methods of emulsifying kerosene or other oils so as to permit of their ready dilution and their consequent use without danger to foliage.

The use of Paris green, first successfully tried against the Colorado potato-beetle, and afterwards used extensively against the cotton-worm, the boll-worm, the canker-worm, and more recently against the codlin moth, plum curculio and many other mandibulate species, marks an era in the warfare against insects. Cheaper arsenical preparations, like London purple, have also proved most satisfactory. Next, perhaps, in importance, is the discovery of the petroleum emulsions, as used against haustellate or sucking insects. Though originally aimed at the cotton-worm and an outgrowth of the cotton-worm investigation under the U. S. Entomological Commission, treatment with these emulsions in their various forms has been extended to all var-eties of bark-lice and plant-lice, as well as to many gnawing insects which chance to feed upon crops which it would be dangerous to spray with arsenicals.

Many variations in the preparation of arsenical mixtures and the kerosene emulsions have already been tried, and doubtless many more yet remain to be tried. Necessary variations in special cases often occur. In my search for a proper wash against the fluted-scale, I met with the necessity of finding a mixture which would penetrate the seemingly impervious wax covering of the egg-sac, or which would harden it to such a degree that the lice, on hatching, would be unable to escape. This was finally accomplished by the addition of resin to the washes, and insects of this character, such as the cottony maple-scale (Pulvinaria innumerabilis), the Florida wax-scale (Ceroplastes Floridensis), the barnacle scale (Ceroplastes cirropediformis) of this country, and the cottony currant-scale of Europe (Pulvinaria ribesti), can now be successfully treated at any stage of their existence without the necessity of waiting for the pregnable period of the hatching and migration of the young lice.

The lessening of the expense of these successful washes is another important point for the future experimenter in this line; and we have before us an immediate need of a careful and exhaustive series of experiments as to the relative effects of the arsenicals and the emulsions upon the foliage of different plants. Our knowledge in this direction at present is slight. Yet we should know with certainty not only just what effect a certain mixture will have upon the vitality of a given plant, but what effect it will have upon this plant in a particular part of the country, with a particular sun exposure, at a certain time of the day, with certain conditions of plant-vigor and precipitation, at a certain season of the year and at a certain period in the life of the plant. We know, from experience, that all of these conditions have strong bearings on the effect of the poisons upon vegetation, yet this line of investigation, first suggested in 1885, has still to be thoroughly followed up. The combination of two classes of insecticides for simultaneous application to two classes of insects affecting the same crop, as a combination of Paris green and kerosene emulsion for the treatment of apple trees affected with bark-lice and apple-worms, or canker-worms, or the same mixture for young cabbages bearing both lice and caterpillars, will afford opportunity for much useful work in the future.