26 THIRTY-FOURTH ANNUAL REPORT OF THE 
organisms are by no means exempt from the pernicious and even fatal 
attacks of these minute parasites. Fishes and flies, silkworms and cica- 
das, the larve and pupe of various moths, beetles and other insects are 
killed by certain fungi that grow in or upon them. So peculiarly liable 
are insects to death from this cause that eminent scientists have sug- 
gested that these parasitic plants may be made available as insecticides 
with which we may combat injurious species. But before this can be ac-. 
complished it is necessary to find a fungus that will inhabit the insects 
we wish to destroy, for it is evident that no single insect-killing fun- 
gus can be used against every noxious insect; and, unfortunately, 
those insects which are most hurtful to our crops do not thus far appear 
to be subject to the attack of any fungus. Parasites and predaceous 
foes of their own class yet appear to be a more promising means of 
diminishing the numbers and ravages of such insects. 
Most of our knowledge of fungi has been acquired within the present 
century. Many thousands of species have been described and classi- 
fied, and new ones are discovered and published almost monthly. But 
much yet remains to be done. The life histories and the true specific 
limits of many comparatively common species are yet to be ascertained. 
In some instances a kind of polymorphism or alternation of generations 
exists and makes investigation more difficult. The minnteness of 
some species and the peculiar conditions necessary for the development 
of others are also obstacles to be overcome before we can claim to fuliy 
understand these organisms. Indeed there is a lower grade of these 
very lowly plants the investigation of which is difficult even with our 
best microscopes. I refer to such organisms as Bacteria, Vibriones, 
Bacilli and Micrococci. To them the putrefaction of animal sub- 
stances is attributed and also of some vegetable substances; they are. 
also charged with the production of some of the most destructive 
maladies of our domestic animals; and the recent investigations of 
Prof. Burrill indicate that they are responsible too for the production 
of those dread diseases of our fruit trees, the *‘ yellows” of the peach 
and the “blight” of the apple and the pear trees, diseases that have . 
hitherto baffled all efforts to ascertain their causes. ‘There are also 
those who believe that many of the contagious diseases of the human 
race are due to similar agencies. It is very probable that this belief 
will yet be supported by abundant evidence; but, if it should not be, 
enough is already known to make it evident that the relations of fungi 
to our material interests and well-being are much more intimate and 
far-reaching than is generally supposed. In view of their relations to 
us and to our food-plants, and of their importance in the economy of 
nature, and of the general lack of information concerning them, I have 
thought it would be well to give a plain and easy account of a few of 
our common species, avoiding, as far as possible, the use of technical 
terms and illustrating the minute parts by enlarged drawings. I have 
selected for this purpose such species as almost any one may find and 
observe if they will examine our corn fields, strawberry plants and 
orchards. 
Ustilago Maydis, Lev. Indian corn Smut. (Plate 3, Figs. 1-3.) 
This fungus can be found in almost any corn field after the corn has 
developed its flowers. he visible part of the fungus consists of more 
