THE PI.ANT WORLD 183 



than on any other. There are several books treating almost exclusively 

 of insect diseases caused by fungi. Among these are Thaxter's " Mono- 

 graph of the Laboulbeniaceae " and Cook's "Vegetable Wasps and 

 Plant Worms," the latter being a more popular work than the other. 

 Besides the books which are devoted to this subject there are numerous 

 articles scattered throughout botanical literature, making an aggregate 

 which is quite voluminous. The Muscardine disease of silkworms is proba- 

 bly of as great economic importance as any of the fungus diseases of insects, 

 although in this country the foul-brood of honey-bees causes more loss than 

 any other one disease of this character. It is very well known that 

 house-flies are very subject to a fungus disease, as are also locusts and 

 chinchbugs. In the latter two cases it has been proposed to destroy the 

 insects in large numbers by means of artificially-raised fungus. This is 

 procured from some of the diseased insects early in the season and pure 

 cultures are made upon artificial media. When the insects get trouble- 

 some by their numbers a few are caught and thoroughly covered with 

 the spores of the fungus. They are then turned loose among the rest in 

 the field, where they scatter the spores and inoculate many others with 

 them. In this way their numbers can be materially reduced when the 

 conditions are right for the rapid development of the fungus. The ex- 

 periments as a rule have not been very successful. 



That insects very often carry fungus spores from one place to another 

 has in many cases been actually proven. The peculiar adaptations of 

 some fungi for this method of distribution are very interesting. The 

 Phalloideae, commonly called ' ' stinkhorns, ' ' exhibit such adaptations to a 

 marked degree. They are of the most fantastic and beautiful shapes, 

 and for this reason have been called "fungus-flowers" by one author. 

 When mature they have quite a tall stem, the spore-bearing portion de- 

 generates into a slimy, sticky mass, and their best-known characteristic 

 becomes very evident. This is one of the vilest odors, if not the worst 

 one, known in the plant kingdom. It very closely resembles the odor 

 of decaying animal matter at its worst. Flies are attracted from far and 

 near by it, and after walking over the sticky, spore-containing mass, they 

 carry away large numbers of the spores to be left everywhere the flies 

 may chance to alight. A curious adaptation of another kind is that of 

 the ergot iClaviceps purpurea) . At the time of the formation of the 

 spores large drops of a sweet liquid are produced and many spores float 

 in the drops. The liquid is eagerly sought by insects and they carry 

 away many spores after getting the fluid. Still another curious case is 

 that of certain fungi which have an agreeable odor by which insects are 

 attracted. Sclerotinia vaccinii, which has a strong, characteristic odor 

 of almonds, is a good example of this class of fungi. Many fungi have 

 spores that are sticky or that have spines such as will catch on the legs 



