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 larvae and pupae 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 minuteness of 

 some species and the peculiar conditions necessary for the development 

 of others are also obstacles to be overcome before we can claim to fully 

 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. 



TJstilago 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. The visible part of the fungus consists of more 



