10 



less commonly found, or on wind pollinated plants. An 

 analogy with the pollen grain suggested to Ludwig that the 

 rough walled spores are disseminated by the agency of insects, 

 and those which are smooth walled by the wind. 



That the bitter rot of apples can be carried by insects was 

 first shown by Clinton (7), who succeeded in inoculating sound 

 apples by keeping them in a moist chamber with some bitter 

 rot apples and some flies of the genus Drosophila. Clinton 

 was of the belief that these flies carried the ascospores from 

 mummied apples to green apples and were thus responsible for 

 a large number of new infections in the spring. Burrill (6) 

 repeated Clinton's experiments with the same positive results, 

 and also gives more data to prove that these flies are capable 

 of spreading the disease. He reaches the conclusion, however, 

 that insects play only a small part in the dissemination of 

 bitter rot in the orchard. 



Another very well known example of spore distribution by 

 insects is found in the carrion fungi. This is especially true 

 of the common stink horn. Phallus impudicus, which is reported 

 as the cause of a root disease of the grape in Hungary 

 (Istvanffy 28, 24). Von Schlechtendal (42) was the first to 

 recognize that the spores of this species are carried by flies, 

 which are attracted by the foetid odor of the slimy mass in 

 which the spores are imbedded. Of the later work on this form 

 we may mention that of Rathay and Haas (40) and of Fulton 

 (12). The former pointed out the special adaptation of the 

 sporophores for insect visitation, and that other insects besides 

 flies visit the mature spore-bearing surfaces. Fulton found 

 by microscopic examination, that thousands of spores cling to 

 the feet and proboscides of the flies, and that the spores are still 

 viable after passing through the digestive tract of flies. Cobb 

 (8) working with a species of Ithyphallus, closely allied to 

 Phallus impudicus and paratitic on sugar cane, has shown that 

 the spores of this fungus also are widely disseminated by flies 

 and other insects. The number of spores per foot print of a 

 fly may be as high as 860,000, and it was shown that these 

 were capable of germinating. Five fly specks contained on an 

 average of 22,400,000 spores, many of which were viable. 



